diff --git a/packages/tui/src/keys.ts b/packages/tui/src/keys.ts
index f997ffb9..c26d0c17 100644
--- a/packages/tui/src/keys.ts
+++ b/packages/tui/src/keys.ts
@@ -971,6 +971,11 @@ export function matchesKey(data: string, keyId: KeyId): boolean {
 			return data === `\x1b${rawCtrlChar(key)}`;
 		}
 
+		if (alt && !ctrl && !shift && !_kittyProtocolActive && key >= "a" && key <= "z") {
+			// Legacy: alt+letter is ESC followed by the letter
+			if (data === `\x1b${key}`) return true;
+		}
+
 		if (ctrl && !shift && !alt) {
 			const raw = rawCtrlChar(key);
 			if (data === raw) return true;
@@ -1073,6 +1078,10 @@ export function parseKey(data: string): string | undefined {
 		if (code >= 1 && code <= 26) {
 			return `ctrl+alt+${String.fromCharCode(code + 96)}`;
 		}
+		// Legacy alt+letter (ESC followed by letter a-z)
+		if (code >= 97 && code <= 122) {
+			return `alt+${String.fromCharCode(code)}`;
+		}
 	}
 	if (data === "\x1b[A") return "up";
 	if (data === "\x1b[B") return "down";
diff --git a/packages/tui/test/keys.test.ts b/packages/tui/test/keys.test.ts
index ef46bae6..ec7ce1d9 100644
--- a/packages/tui/test/keys.test.ts
+++ b/packages/tui/test/keys.test.ts
@@ -149,6 +149,12 @@ describe("matchesKey", () => {
 			assert.strictEqual(parseKey("\x1bB"), "alt+left");
 			assert.strictEqual(matchesKey("\x1bF", "alt+right"), true);
 			assert.strictEqual(parseKey("\x1bF"), "alt+right");
+			assert.strictEqual(matchesKey("\x1ba", "alt+a"), true);
+			assert.strictEqual(parseKey("\x1ba"), "alt+a");
+			assert.strictEqual(matchesKey("\x1by", "alt+y"), true);
+			assert.strictEqual(parseKey("\x1by"), "alt+y");
+			assert.strictEqual(matchesKey("\x1bz", "alt+z"), true);
+			assert.strictEqual(parseKey("\x1bz"), "alt+z");
 
 			setKittyProtocolActive(true);
 			assert.strictEqual(matchesKey("\x1b ", "alt+space"), false);
@@ -161,6 +167,10 @@ describe("matchesKey", () => {
 			assert.strictEqual(parseKey("\x1bB"), undefined);
 			assert.strictEqual(matchesKey("\x1bF", "alt+right"), false);
 			assert.strictEqual(parseKey("\x1bF"), undefined);
+			assert.strictEqual(matchesKey("\x1ba", "alt+a"), false);
+			assert.strictEqual(parseKey("\x1ba"), undefined);
+			assert.strictEqual(matchesKey("\x1by", "alt+y"), false);
+			assert.strictEqual(parseKey("\x1by"), undefined);
 			setKittyProtocolActive(false);
 		});