diff --git a/codex-rs/tui/src/bottom_pane/chat_composer.rs b/codex-rs/tui/src/bottom_pane/chat_composer.rs
index 446563a19..f64a824f4 100644
--- a/codex-rs/tui/src/bottom_pane/chat_composer.rs
+++ b/codex-rs/tui/src/bottom_pane/chat_composer.rs
@@ -1,3 +1,4 @@
+use crate::key_hint::has_ctrl_or_alt;
 use crossterm::event::KeyCode;
 use crossterm::event::KeyEvent;
 use crossterm::event::KeyEventKind;
@@ -1103,8 +1104,7 @@ impl ChatComposer {
             ..
         } = input
         {
-            let has_ctrl_or_alt =
-                modifiers.contains(KeyModifiers::CONTROL) || modifiers.contains(KeyModifiers::ALT);
+            let has_ctrl_or_alt = has_ctrl_or_alt(modifiers);
             if !has_ctrl_or_alt {
                 // Non-ASCII characters (e.g., from IMEs) can arrive in quick bursts and be
                 // misclassified by paste heuristics. Flush any active burst buffer and insert
@@ -1174,8 +1174,7 @@ impl ChatComposer {
         } = input;
         match code {
             KeyCode::Char(_) => {
-                let has_ctrl_or_alt = modifiers.contains(KeyModifiers::CONTROL)
-                    || modifiers.contains(KeyModifiers::ALT);
+                let has_ctrl_or_alt = has_ctrl_or_alt(modifiers);
                 if has_ctrl_or_alt {
                     self.paste_burst.clear_window_after_non_char();
                 }
diff --git a/codex-rs/tui/src/bottom_pane/textarea.rs b/codex-rs/tui/src/bottom_pane/textarea.rs
index 0a7faa4fc..03de33681 100644
--- a/codex-rs/tui/src/bottom_pane/textarea.rs
+++ b/codex-rs/tui/src/bottom_pane/textarea.rs
@@ -1,3 +1,4 @@
+use crate::key_hint::is_altgr;
 use crossterm::event::KeyCode;
 use crossterm::event::KeyEvent;
 use crossterm::event::KeyModifiers;
@@ -247,16 +248,13 @@ impl TextArea {
             } if modifiers == (KeyModifiers::CONTROL | KeyModifiers::ALT) => {
                 self.delete_backward_word()
             },
+            // Windows AltGr generates ALT|CONTROL; treat as a plain character input unless
+            // we match a specific Control+Alt binding above.
             KeyEvent {
                 code: KeyCode::Char(c),
                 modifiers,
                 ..
-            } if modifiers.contains(KeyModifiers::ALT)
-                && modifiers.contains(KeyModifiers::CONTROL) =>
-            {
-                // AltGr on many keyboards reports as Ctrl+Alt; treat it as a literal char.
-                self.insert_str(&c.to_string());
-            },
+            } if is_altgr(modifiers) => self.insert_str(&c.to_string()),
             KeyEvent {
                 code: KeyCode::Backspace,
                 modifiers: KeyModifiers::ALT,
@@ -1464,6 +1462,7 @@ mod tests {
         assert_eq!(t.cursor(), 3);
     }
 
+    #[cfg_attr(not(windows), ignore = "AltGr modifier only applies on Windows")]
     #[test]
     fn altgr_ctrl_alt_char_inserts_literal() {
         let mut t = ta_with("");
diff --git a/codex-rs/tui/src/key_hint.rs b/codex-rs/tui/src/key_hint.rs
index 1126b8023..6272ab0df 100644
--- a/codex-rs/tui/src/key_hint.rs
+++ b/codex-rs/tui/src/key_hint.rs
@@ -89,3 +89,19 @@ impl From<&KeyBinding> for Span<'static> {
 fn key_hint_style() -> Style {
     Style::default().dim()
 }
+
+pub(crate) fn has_ctrl_or_alt(mods: KeyModifiers) -> bool {
+    (mods.contains(KeyModifiers::CONTROL) || mods.contains(KeyModifiers::ALT)) && !is_altgr(mods)
+}
+
+#[cfg(windows)]
+#[inline]
+pub(crate) fn is_altgr(mods: KeyModifiers) -> bool {
+    mods.contains(KeyModifiers::ALT) && mods.contains(KeyModifiers::CONTROL)
+}
+
+#[cfg(not(windows))]
+#[inline]
+pub(crate) fn is_altgr(_mods: KeyModifiers) -> bool {
+    false
+}