diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 1683f89136..3c0e658e7b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2967,6 +2967,7 @@ jobs:
             test_issue_610_smoke \
             test_issue_640_navstack_textfield \
             test_issue_763_reactive_textfield \
+            test_issue_10155_textfield_singleline \
             test_issue_764_state_at_module_init \
             test_ramda_user_import \
             test_take_screenshot \
diff --git a/changelog.d/10157-macos-textfield-single-line.md b/changelog.d/10157-macos-textfield-single-line.md
new file mode 100644
index 0000000000..901fa8c2b0
--- /dev/null
+++ b/changelog.d/10157-macos-textfield-single-line.md
@@ -0,0 +1,8 @@
+Fixed macOS `TextField` wrapping to multiple lines when its text was wider than
+the field. `perry-ui-macos`'s `create()` built the field from
+`NSTextField::textFieldWithString`, whose cell wraps and grows, and never
+overrode it — so a fixed-width field grew tall instead of scrolling, unlike
+every other backend. The cell is now configured for single-line editing
+(`usesSingleLineMode`, `scrollable`, `wraps = false`, clipping line-break mode),
+matching iOS / GTK4 / Android / Windows. Multiline input keeps its own widget,
+`TextArea`.
diff --git a/crates/perry-ui-macos/src/widgets/textfield.rs b/crates/perry-ui-macos/src/widgets/textfield.rs
index c6ecb24828..c879ed2e5c 100644
--- a/crates/perry-ui-macos/src/widgets/textfield.rs
+++ b/crates/perry-ui-macos/src/widgets/textfield.rs
@@ -2,7 +2,7 @@ use crate::ffi::{js_gc_pin_user_ptr, js_string_from_bytes};
 use objc2::rc::Retained;
 use objc2::runtime::{AnyObject, Sel};
 use objc2::{define_class, msg_send, AnyThread, DefinedClass};
-use objc2_app_kit::{NSTextField, NSView};
+use objc2_app_kit::{NSLineBreakMode, NSTextField, NSView};
 use objc2_foundation::{
     MainThreadMarker, NSNotification, NSNotificationCenter, NSObject, NSString,
 };
@@ -197,6 +197,17 @@ pub fn create(placeholder_ptr: *const u8, on_change: f64) -> i64 {
         text_field.setEditable(true);
         text_field.setBezeled(true);
 
+        // Single-line, to match TextField on every other backend; TextArea is
+        // the multiline widget. textFieldWithString: hands back a cell that
+        // wraps and grows tall, so a fixed-width field must be told to keep one
+        // line and scroll horizontally instead.
+        if let Some(cell) = text_field.cell() {
+            cell.setUsesSingleLineMode(true);
+            cell.setScrollable(true);
+            cell.setWraps(false);
+            cell.setLineBreakMode(NSLineBreakMode::ByClipping);
+        }
+
         let view: Retained<NSView> = Retained::cast_unchecked(text_field);
         let handle = super::register_widget(view);
 
diff --git a/test-files/test_issue_10155_textfield_singleline.ts b/test-files/test_issue_10155_textfield_singleline.ts
new file mode 100644
index 0000000000..dee9a83163
--- /dev/null
+++ b/test-files/test_issue_10155_textfield_singleline.ts
@@ -0,0 +1,20 @@
+// Smoke test for issue #10155: a fixed-width editable TextField on macOS must
+// stay one line and scroll horizontally, not wrap and grow tall.
+// Run the built app and confirm the long value shows on one line inside the
+// 220px-wide field, matching a normal single-line NSTextField.
+import { App, VStack, Text, TextField, State, stateBindTextfield, widgetSetWidth } from "perry/ui"
+
+const text = State("assignee = currentUser() AND statusCategory != Done AND project = SU")
+const field = TextField("query...", (value: string) => text.set(value))
+stateBindTextfield(text, field)
+widgetSetWidth(field, 220)
+
+App({
+    title: "issue 10155 single-line TextField",
+    width: 300,
+    height: 160,
+    body: VStack(12, [
+        Text("Field below must stay one line and scroll, not wrap:"),
+        field,
+    ]),
+})