diff --git a/src/scripts/choices.js b/src/scripts/choices.js
index 9b41d56..f06da56 100644
--- a/src/scripts/choices.js
+++ b/src/scripts/choices.js
@@ -1350,7 +1350,7 @@ class Choices {
         therefore does not have the value of the key.
       */
       if (this._isSelectOneElement) {
-        this.input.value += keyString;
+        this.input.value += keyString.toLowerCase();
       }
     }
 
diff --git a/src/scripts/choices.test.js b/src/scripts/choices.test.js
index 37dd3ef..e7b2079 100644
--- a/src/scripts/choices.test.js
+++ b/src/scripts/choices.test.js
@@ -2118,7 +2118,7 @@ describe('choices', () => {
                     keyCode: KEY_CODES.A_KEY,
                   });
 
-                  expect(instance.input.value).to.contain('A');
+                  expect(instance.input.value).to.contain('a');
                 });
               });
 
@@ -2132,7 +2132,7 @@ describe('choices', () => {
                     keyCode: KEY_CODES.A_KEY,
                   });
 
-                  expect(instance.input.value).to.not.contain('A');
+                  expect(instance.input.value).to.not.contain('a');
                 });
               });
             });