diff --git a/docs/07-supported-chains.md b/docs/07-supported-chains.md
index f9e8c665..a02a88cb 100644
--- a/docs/07-supported-chains.md
+++ b/docs/07-supported-chains.md
@@ -58,6 +58,7 @@ Each network has a canonical chain identifier. Endpoint discovery and transport
 | BSC | `eip155:56` |
 | Avalanche | `eip155:43114` |
 | Etherlink | `eip155:42793` |
+| Monad | `eip155:143` |
 | Tempo | `eip155:4217` |
 | Hyperliquid | `eip155:999` |
 
@@ -93,6 +94,7 @@ optimism  → eip155:10
 bsc       → eip155:56
 avalanche → eip155:43114
 etherlink → eip155:42793
+monad     → eip155:143
 tempo       → eip155:4217
 hyperliquid → eip155:999
 solana    → solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp
diff --git a/ows/crates/ows-core/src/chain.rs b/ows/crates/ows-core/src/chain.rs
index cbe9380d..43a362a7 100644
--- a/ows/crates/ows-core/src/chain.rs
+++ b/ows/crates/ows-core/src/chain.rs
@@ -123,6 +123,11 @@ pub const KNOWN_CHAINS: &[Chain] = &[
         chain_type: ChainType::Evm,
         chain_id: "eip155:42793",
     },
+    Chain {
+        name: "monad",
+        chain_type: ChainType::Evm,
+        chain_id: "eip155:143",
+    },
     Chain {
         name: "solana",
         chain_type: ChainType::Solana,
@@ -501,6 +506,22 @@ mod tests {
         assert_eq!(chain.chain_id, "eip155:42793");
     }
 
+    #[test]
+    fn test_parse_chain_monad_alias() {
+        let chain = parse_chain("monad").unwrap();
+        assert_eq!(chain.name, "monad");
+        assert_eq!(chain.chain_type, ChainType::Evm);
+        assert_eq!(chain.chain_id, "eip155:143");
+    }
+
+    #[test]
+    fn test_parse_chain_monad_caip2() {
+        let chain = parse_chain("eip155:143").unwrap();
+        assert_eq!(chain.name, "monad");
+        assert_eq!(chain.chain_type, ChainType::Evm);
+        assert_eq!(chain.chain_id, "eip155:143");
+    }
+
     #[test]
     fn test_parse_chain_caip2() {
         let chain = parse_chain("eip155:42161").unwrap();
diff --git a/ows/crates/ows-core/src/config.rs b/ows/crates/ows-core/src/config.rs
index 29c92dfb..9221c844 100644
--- a/ows/crates/ows-core/src/config.rs
+++ b/ows/crates/ows-core/src/config.rs
@@ -42,6 +42,7 @@ impl Config {
             "eip155:43114".into(),
             "https://api.avax.network/ext/bc/C/rpc".into(),
         );
+        rpc.insert("eip155:143".into(), "https://rpc.monad.xyz".into());
         rpc.insert(
             "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp".into(),
             "https://api.mainnet-beta.solana.com".into(),
@@ -199,6 +200,7 @@ mod tests {
             Some("https://polygon-rpc.com")
         );
         assert_eq!(config.rpc_url("eip155:9745"), Some("https://rpc.plasma.to"));
+        assert_eq!(config.rpc_url("eip155:143"), Some("https://rpc.monad.xyz"));
         assert_eq!(
             config.rpc_url("solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"),
             Some("https://api.mainnet-beta.solana.com")
@@ -266,7 +268,7 @@ mod tests {
     fn test_load_or_default_nonexistent() {
         let config = Config::load_or_default_from(std::path::Path::new("/nonexistent/config.json"));
         // Should have all default RPCs
-        assert_eq!(config.rpc.len(), 23);
+        assert_eq!(config.rpc.len(), 24);
         assert_eq!(config.rpc_url("eip155:1"), Some("https://eth.llamarpc.com"));
         assert_eq!(
             config.rpc_url("near:mainnet"),
diff --git a/ows/crates/ows-pay/src/chains.rs b/ows/crates/ows-pay/src/chains.rs
index 6ab1b96a..a3cf6c2e 100644
--- a/ows/crates/ows-pay/src/chains.rs
+++ b/ows/crates/ows-pay/src/chains.rs
@@ -46,6 +46,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn resolve_monad_name() {
+        assert_eq!(resolve_chain_type("monad"), Some(ChainType::Evm));
+    }
+
+    #[test]
+    fn resolve_monad_caip2() {
+        assert_eq!(resolve_chain_type("eip155:143"), Some(ChainType::Evm));
+    }
+
+    #[test]
+    fn display_monad() {
+        assert_eq!(display_name("monad"), "monad");
+        assert_eq!(display_name("eip155:143"), "monad");
+    }
+
     #[test]
     fn resolve_unknown_caip2_known_namespace() {
         // Chain not in KNOWN_CHAINS but namespace is recognized.