diff --git a/app/src/main/kotlin/com/wire/android/ui/authentication/create/common/handle/UsernameTextField.kt b/app/src/main/kotlin/com/wire/android/ui/authentication/create/common/handle/UsernameTextField.kt
index ac1c7ca2b82..07c8c8e93c0 100644
--- a/app/src/main/kotlin/com/wire/android/ui/authentication/create/common/handle/UsernameTextField.kt
+++ b/app/src/main/kotlin/com/wire/android/ui/authentication/create/common/handle/UsernameTextField.kt
@@ -34,6 +34,7 @@ import com.wire.android.ui.common.error.CoreFailureErrorDialog
 import com.wire.android.ui.common.textfield.DefaultEmail
 import com.wire.android.ui.common.textfield.WireTextField
 import com.wire.android.ui.common.textfield.WireTextFieldState
+import com.wire.android.ui.common.textfield.forceLowercase
 import com.wire.android.ui.common.textfield.maxLengthWithCallback
 import com.wire.android.ui.common.textfield.patternWithCallback
 import com.wire.android.ui.theme.wireDimensions
@@ -56,6 +57,7 @@ fun UsernameTextField(
             placeholderText = stringResource(R.string.create_account_username_placeholder),
             labelText = stringResource(R.string.create_account_username_label),
             inputTransformation = InputTransformation
+                .forceLowercase()
                 .patternWithCallback(Patterns.HANDLE, animate)
                 .maxLengthWithCallback(255, animate),
             leadingIcon = {
diff --git a/app/src/main/kotlin/com/wire/android/ui/common/textfield/InputTransformations.kt b/app/src/main/kotlin/com/wire/android/ui/common/textfield/InputTransformations.kt
index 01a8c8e6c77..a8a4ad7b44c 100644
--- a/app/src/main/kotlin/com/wire/android/ui/common/textfield/InputTransformations.kt
+++ b/app/src/main/kotlin/com/wire/android/ui/common/textfield/InputTransformations.kt
@@ -76,6 +76,15 @@ class PatternFilterWithCallback(private val pattern: Pattern, private val onInco
     }
 }
 
+fun InputTransformation.forceLowercase(): InputTransformation =
+    this.then(ForceLowercaseTransformation())
+
+class ForceLowercaseTransformation : InputTransformation {
+    override fun TextFieldBuffer.transformInput() {
+        replace(0, length, asCharSequence().toString().lowercase())
+    }
+}
+
 @Stable
 fun InputTransformation.patternWithCallback(pattern: Pattern, onIncorrectChangesFound: () -> Unit): InputTransformation =
     this.then(PatternFilterWithCallback(pattern, onIncorrectChangesFound))