diff --git a/lib/wreq.rb b/lib/wreq.rb
index da498ff..b204f0b 100644
--- a/lib/wreq.rb
+++ b/lib/wreq.rb
@@ -25,7 +25,7 @@ module Wreq
     # @param method [Wreq::Method] HTTP method to use
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -56,7 +56,7 @@ def self.request(method, url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -87,7 +87,7 @@ def self.get(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -118,7 +118,7 @@ def self.head(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -149,7 +149,7 @@ def self.post(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -180,7 +180,7 @@ def self.put(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -211,7 +211,7 @@ def self.delete(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -242,7 +242,7 @@ def self.options(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
@@ -273,7 +273,7 @@ def self.trace(url, **options)
     #
     # @param url [String] Target URL
     # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-    # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+    # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
     # @param default_headers [Hash{String=>String}, nil] Default headers to merge
     # @param query [Hash, nil] URL query parameters
     # @param auth [String, nil] Authorization header value
diff --git a/lib/wreq_ruby/client.rb b/lib/wreq_ruby/client.rb
index 8f4771a..7718c01 100644
--- a/lib/wreq_ruby/client.rb
+++ b/lib/wreq_ruby/client.rb
@@ -38,6 +38,8 @@ class Client
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Default headers to include
       #   in every request. Header names are case-insensitive. These headers
       #   can be overridden on a per-request basis.
+      # @param orig_headers [Array<String>, nil] Original header names used to
+      #   preserve raw header order and HTTP/1 case-sensitive header handling.
       #
       # @param referer [Boolean, nil] Whether to automatically send Referer
       #   headers when following redirects. When true, the previous URL will
@@ -237,7 +239,7 @@ def self.new(**options)
       # @param method [Wreq::Method] HTTP method to use
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -268,7 +270,7 @@ def request(method, url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -299,7 +301,7 @@ def get(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -330,7 +332,7 @@ def head(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -361,7 +363,7 @@ def post(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -392,7 +394,7 @@ def put(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -423,7 +425,7 @@ def delete(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -454,7 +456,7 @@ def options(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
@@ -485,7 +487,7 @@ def trace(url, **options)
       #
       # @param url [String] Target URL
       # @param headers [Wreq::Headers, Hash{String=>String}, nil] Custom headers for this request
-      # @param orig_headers [Hash{String=>String}, nil] Original headers (raw, unmodified)
+      # @param orig_headers [Array<String>, nil] Original header names used to preserve raw header order and HTTP/1 case-sensitive header handling
       # @param default_headers [Hash{String=>String}, nil] Default headers to merge
       # @param query [Hash, nil] URL query parameters
       # @param auth [String, nil] Authorization header value
diff --git a/src/client.rs b/src/client.rs
index e945bfa..436c3a0 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -10,10 +10,7 @@ use magnus::{
     Module, Object, RHash, RModule, Ruby, TryConvert, Value, function, method, typed_data::Obj,
 };
 use serde::Deserialize;
-use wreq::{
-    Proxy,
-    header::{HeaderValue, OrigHeaderMap},
-};
+use wreq::{Proxy, header::HeaderValue};
 
 use crate::{
     client::{req::execute_request, resp::Response},
@@ -22,7 +19,7 @@ use crate::{
     error::wreq_error_to_magnus,
     extractor::Extractor,
     gvl,
-    header::Headers,
+    header::{Headers, OrigHeaders},
     http::Method,
 };
 
@@ -40,7 +37,7 @@ struct Builder {
     headers: Option<Headers>,
     /// The original headers to use for the client.
     #[serde(skip)]
-    orig_headers: Option<OrigHeaderMap>,
+    orig_headers: Option<OrigHeaders>,
     /// Whether to use referer.
     referer: Option<bool>,
     /// Whether to allow redirects.
@@ -143,6 +140,10 @@ impl Builder {
             builder.headers = Some(Headers::try_convert(v)?);
         }
 
+        if let Some(v) = hash.get(ruby.to_symbol(stringify!(orig_headers))) {
+            builder.orig_headers = Some(OrigHeaders::try_convert(v)?);
+        }
+
         if let Some(v) = hash.get(ruby.to_symbol(stringify!(cookie_provider))) {
             builder.cookie_provider = Some((*Obj::<Jar>::try_convert(v)?).clone());
         }
@@ -152,7 +153,6 @@ impl Builder {
         }
 
         builder.user_agent = Extractor::<HeaderValue>::try_convert(*keyword)?.into_inner();
-        builder.orig_headers = Extractor::<OrigHeaderMap>::try_convert(*keyword)?.into_inner();
         builder.proxy = Extractor::<Proxy>::try_convert(*keyword)?.into_inner();
 
         Ok(builder)
@@ -175,14 +175,19 @@ impl Client {
                 // User agent options.
                 apply_option!(set_if_some, builder, params.user_agent, user_agent);
 
-                // Default headers options.
+                // Headers options.
                 apply_option!(
                     set_if_some_into_inner,
                     builder,
                     params.headers,
                     default_headers
                 );
-                apply_option!(set_if_some, builder, params.orig_headers, orig_headers);
+                apply_option!(
+                    set_if_some_inner,
+                    builder,
+                    params.orig_headers,
+                    orig_headers
+                );
 
                 // Allow redirects options.
                 apply_option!(set_if_some, builder, params.referer, referer);
diff --git a/src/client/req.rs b/src/client/req.rs
index 6cd4791..45b4547 100644
--- a/src/client/req.rs
+++ b/src/client/req.rs
@@ -3,7 +3,7 @@ use std::{net::IpAddr, time::Duration};
 use http::header;
 use magnus::{RHash, TryConvert, typed_data::Obj, value::ReprValue};
 use serde::Deserialize;
-use wreq::{Client, Proxy, header::OrigHeaderMap};
+use wreq::{Client, Proxy};
 
 use super::body::{Body, Form, Json};
 use crate::{
@@ -12,7 +12,7 @@ use crate::{
     emulate::Emulation,
     error::wreq_error_to_magnus,
     extractor::Extractor,
-    header::Headers,
+    header::{Headers, OrigHeaders},
     http::{Method, Version},
     rt,
 };
@@ -54,7 +54,7 @@ pub struct Request {
 
     /// The original headers to use for the request.
     #[serde(skip)]
-    orig_headers: Option<OrigHeaderMap>,
+    orig_headers: Option<OrigHeaders>,
 
     /// The cookies to use for the request.
     #[serde(skip)]
@@ -120,6 +120,10 @@ impl Request {
             builder.headers = Some(Headers::try_convert(v)?);
         }
 
+        if let Some(v) = hash.get(ruby.to_symbol(stringify!(orig_headers))) {
+            builder.orig_headers = Some(OrigHeaders::try_convert(v)?);
+        }
+
         if let Some(v) = hash.get(ruby.to_symbol(stringify!(cookies))) {
             builder.cookies = Some(Cookies::try_convert(v)?);
         }
@@ -129,7 +133,6 @@ impl Request {
         }
 
         builder.proxy = Extractor::<Proxy>::try_convert(keyword)?.into_inner();
-        builder.orig_headers = Extractor::<OrigHeaderMap>::try_convert(keyword)?.into_inner();
 
         Ok(builder)
     }
@@ -179,7 +182,12 @@ pub fn execute_request<U: AsRef<str>>(
 
         // Headers options.
         apply_option!(set_if_some_into_inner, builder, request.headers, headers);
-        apply_option!(set_if_some, builder, request.orig_headers, orig_headers);
+        apply_option!(
+            set_if_some_inner,
+            builder,
+            request.orig_headers,
+            orig_headers
+        );
         apply_option!(
             set_if_some,
             builder,
diff --git a/src/error.rs b/src/error.rs
index 6cf9521..80802ea 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -117,6 +117,14 @@ pub fn header_value_error_to_magnus(err: wreq::header::InvalidHeaderValue) -> Ma
     )
 }
 
+/// Map type/value errors to corresponding [`magnus::Error`]
+pub fn type_value_error_to_magnus(err: &str) -> MagnusError {
+    MagnusError::new(
+        ruby!().get_inner(&BUILDER_ERROR),
+        format!("type error: {err}"),
+    )
+}
+
 /// Map [`wreq::Error`] to corresponding [`magnus::Error`]
 pub fn wreq_error_to_magnus(err: wreq::Error) -> MagnusError {
     let error_msg = err.to_string();
diff --git a/src/extractor.rs b/src/extractor.rs
index e16d548..63df29a 100644
--- a/src/extractor.rs
+++ b/src/extractor.rs
@@ -1,6 +1,6 @@
 use magnus::{RArray, RHash, RString, Ruby, TryConvert, r_hash::ForEach};
 use wreq::{
-    Proxy, Version,
+    Proxy,
     header::{HeaderMap, HeaderName, HeaderValue, OrigHeaderMap},
 };
 
@@ -32,27 +32,6 @@ where
     }
 }
 
-// ===== impl Extractor<Version> =====
-
-impl ExtractorName for Version {
-    const NAME: &str = "version";
-}
-
-impl TryConvert for Extractor<Version> {
-    fn try_convert(value: magnus::Value) -> Result<Self, magnus::Error> {
-        let keyword = RHash::try_convert(value)?;
-        if let Some(version_val) = keyword.get(Version::NAME) {
-            return <&crate::http::Version>::try_convert(version_val)
-                .cloned()
-                .map(crate::http::Version::into_ffi)
-                .map(Some)
-                .map(Extractor);
-        }
-
-        Ok(Extractor(None))
-    }
-}
-
 // ===== impl Extractor<HeaderValue> =====
 
 impl ExtractorName for HeaderValue {
diff --git a/src/header.rs b/src/header.rs
index aa1cf33..cf8bd6f 100644
--- a/src/header.rs
+++ b/src/header.rs
@@ -9,8 +9,11 @@ use magnus::{
     r_hash::ForEach,
     typed_data::{Inspect, Obj},
 };
+use wreq::header::OrigHeaderMap;
 
-use crate::error::{header_name_error_to_magnus, header_value_error_to_magnus};
+use crate::error::{
+    header_name_error_to_magnus, header_value_error_to_magnus, type_value_error_to_magnus,
+};
 
 /// HTTP headers collection with read and write operations.
 ///
@@ -20,6 +23,9 @@ use crate::error::{header_name_error_to_magnus, header_value_error_to_magnus};
 #[magnus::wrap(class = "Wreq::Headers", free_immediately, size)]
 pub struct Headers(pub RefCell<HeaderMap>);
 
+/// A map from header names to their original casing as received in an HTTP message.
+pub struct OrigHeaders(pub OrigHeaderMap);
+
 struct HeaderIter {
     inner: http::header::IntoIter<HeaderValue>,
     next_name: Option<HeaderName>,
@@ -166,6 +172,23 @@ impl TryConvert for Headers {
     }
 }
 
+// ===== impl OrigHeaders =====
+
+impl TryConvert for OrigHeaders {
+    fn try_convert(value: magnus::Value) -> Result<Self, magnus::Error> {
+        let mut map = OrigHeaderMap::new();
+
+        let rarray = RArray::from_value(value)
+            .ok_or_else(|| type_value_error_to_magnus("Expected an array of strings"))?;
+
+        for value in rarray.into_iter().flat_map(RString::from_value) {
+            map.insert(value.to_bytes());
+        }
+
+        Ok(Self(map))
+    }
+}
+
 // ===== impl HeaderIter =====
 
 impl Iterator for HeaderIter {
diff --git a/test/orig_header_test.rb b/test/orig_header_test.rb
new file mode 100644
index 0000000..a45b420
--- /dev/null
+++ b/test/orig_header_test.rb
@@ -0,0 +1,115 @@
+require "test_helper"
+
+class OrigHeaderTest < Minitest::Test
+  URL = "https://tls.browserleaks.com/http1"
+
+  CASES = [
+    {
+      name: "mixed_case_descending",
+      headers: {
+        "X-Zeta-Token" => "zeta",
+        "x-alpha-key" => "alpha",
+        "X-MiXeD-CaSe" => "mixed"
+      },
+      orig_headers: ["X-Zeta-Token", "x-alpha-key", "X-MiXeD-CaSe"]
+    },
+    {
+      name: "reverse_alpha_order",
+      headers: {
+        "X-Third" => "3",
+        "X-Second" => "2",
+        "X-First" => "1"
+      },
+      orig_headers: ["X-Third", "X-Second", "X-First"]
+    },
+    {
+      name: "preserve_weird_casing",
+      headers: {
+        "x-a" => "a",
+        "X-B" => "b",
+        "x-C" => "c"
+      },
+      orig_headers: ["x-C", "x-a", "X-B"]
+    },
+    {
+      name: "interleaved_tokens",
+      headers: {
+        "X-Token-3" => "v3",
+        "X-Token-1" => "v1",
+        "X-Token-2" => "v2"
+      },
+      orig_headers: ["X-Token-1", "X-Token-2", "X-Token-3"]
+    }
+  ].freeze
+
+  def test_client_default_orig_headers_preserves_header_order_in_multiple_shuffled_cases
+    CASES.each do |kase|
+      client = Wreq::Client.new(
+        headers: kase[:headers],
+        orig_headers: kase[:orig_headers]
+      )
+
+      response = client.get(URL, version: Wreq::Version::HTTP_11)
+      assert_equal 200, response.code, "case=#{kase[:name]}"
+
+      echoed_headers = extract_http1_headers(response.json, kase[:name])
+      assert_header_order(echoed_headers, kase[:orig_headers], kase[:name])
+      assert_header_values(echoed_headers, kase[:headers], kase[:name])
+    end
+  end
+
+  def test_module_request_orig_headers_preserves_header_order_in_multiple_shuffled_cases
+    CASES.each do |kase|
+      response = Wreq.get(
+        URL,
+        headers: kase[:headers],
+        orig_headers: kase[:orig_headers],
+        version: Wreq::Version::HTTP_11
+      )
+      assert_equal 200, response.code, "case=#{kase[:name]}"
+
+      echoed_headers = extract_http1_headers(response.json, kase[:name])
+      assert_header_order(echoed_headers, kase[:orig_headers], kase[:name])
+      assert_header_values(echoed_headers, kase[:headers], kase[:name])
+    end
+  end
+
+  private
+
+  def extract_http1_headers(json, case_name)
+    http1 = fetch_by_name(json, "http1")
+    refute_nil http1, "case=#{case_name}: expected JSON key 'http1', got #{json.keys.inspect}"
+
+    headers = fetch_by_name(http1, "headers")
+    refute_nil headers, "case=#{case_name}: expected JSON key 'http1.headers'"
+    headers
+  end
+
+  def fetch_by_name(hash_like, key_name)
+    return hash_like[key_name] if hash_like.respond_to?(:key?) && hash_like.key?(key_name)
+    return hash_like[key_name.to_sym] if hash_like.respond_to?(:key?) && hash_like.key?(key_name.to_sym)
+
+    pair = hash_like.find { |k, _| k.to_s == key_name }
+    pair&.last
+  end
+
+  def assert_header_order(echoed_headers, ordered_names, case_name)
+    echoed_keys = echoed_headers.keys
+    positions = ordered_names.map do |expected_name|
+      index = echoed_keys.index(expected_name)
+      refute_nil index, "case=#{case_name}: expected header to exist in echo: #{expected_name}"
+      index
+    end
+
+    assert_equal positions.sort, positions,
+      "case=#{case_name}: expected header order #{ordered_names.inspect}, got keys #{echoed_keys.inspect}"
+  end
+
+  def assert_header_values(echoed_headers, expected_headers, case_name)
+    expected_headers.each do |name, expected_value|
+      assert echoed_headers.key?(name),
+        "case=#{case_name}: expected exact-case header name #{name}, got #{echoed_headers.keys.inspect}"
+      assert_equal expected_value, echoed_headers[name]
+    end
+  end
+end