diff --git a/README.md b/README.md
index 4f5a5a1..06a20ca 100644
--- a/README.md
+++ b/README.md
@@ -108,3 +108,18 @@ These settings are available:
 npm install
 npm test
 ```
+
+## Troubleshooting
+
+### Combobox options must have unique IDs
+
+Passing a combobox whose options lack IDs results in the following console warning.
+
+> Combobox options must have unique IDs
+> See https://github.com/github/combobox-nav/?tab=readme-ov-file#combobox-options-must-have-unique-ids
+
+Without the IDs we lack a unique identifier for [`aria-activedescendant`](https://www.w3.org/WAI/ARIA/apg/practices/keyboard-interface/#kbd_focus_activedescendant) to reference. As a result, screen readers are unable to announce which option is currently selected.
+
+You can remove this warning by setting IDs on every option in the combobox.
+
+
diff --git a/src/index.ts b/src/index.ts
index 35efe6e..9fe1d5e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -49,6 +49,13 @@ export default class Combobox {
       list.id = `combobox-${Math.random().toString().slice(2, 6)}`
     }
 
+    if (list.querySelectorAll('[role="option"]:not([id])').length > 0) {
+      console.warn([
+        'Combobox options must have unique IDs',
+        'See https://github.com/github/combobox-nav/?tab=readme-ov-file#combobox-options-must-have-unique-ids',
+      ].join('\n'))
+    }
+
     this.ctrlBindings = !!navigator.userAgent.match(/Macintosh/)
 
     this.keyboardEventHandler = event => keyboardBindings(event, this)