diff --git a/README.md b/README.md
index 60e56d3..d42076b 100644
--- a/README.md
+++ b/README.md
@@ -137,6 +137,8 @@ catch (\Delight\Auth\TooManyRequestsException $e) {
 }
 ```
 
+If you want to sign in with usernames on the other hand, either in addition to the login via email address or as a replacement, that's possible as well. Simply call the method `loginWithUsername` instead of method `login`. Then, instead of catching `InvalidEmailException`, make sure to catch both `UnknownUsernameException` and `AmbiguousUsernameException`. You may also want to read the notes about the uniqueness of usernames in the section that explains how to [sign up new users](#registration-sign-up).
+
 ### Email verification
 
 Extract the selector and token from the URL that the user clicked on in the verification email.
diff --git a/src/Auth.php b/src/Auth.php
index 04fcce1..dfa9d3c 100644
--- a/src/Auth.php
+++ b/src/Auth.php
@@ -254,7 +254,7 @@ class Auth {
 	}
 
 	/**
-	 * Attempts to sign in a user
+	 * Attempts to sign in a user with their email address and password
 	 *
 	 * @param string $email the user's email address
 	 * @param string $password the user's password
@@ -268,6 +268,26 @@ class Auth {
 		$this->authenticateUserInternal($password, $email, null, $rememberDuration);
 	}
 
+	/**
+	 * Attempts to sign in a user with their username and password
+	 *
+	 * When using this method to authenticate users, you should ensure that usernames are unique
+	 *
+	 * Consistently using {@see registerWithUniqueUsername} instead of {@see register} can be helpful
+	 *
+	 * @param string $username the user's username
+	 * @param string $password the user's password
+	 * @param int|bool|null $rememberDuration (optional) the duration in seconds to keep the user logged in ("remember me"), e.g. `60 * 60 * 24 * 365.25` for one year
+	 * @throws UnknownUsernameException if the specified username does not exist
+	 * @throws AmbiguousUsernameException if the specified username is ambiguous, i.e. there are multiple users with that name
+	 * @throws InvalidPasswordException if the password was invalid
+	 * @throws EmailNotVerifiedException if the email address has not been verified yet via confirmation email
+	 * @throws AuthError if an internal problem occurred (do *not* catch)
+	 */
+	public function loginWithUsername($username, $password, $rememberDuration = null) {
+		$this->authenticateUserInternal($password, null, $username, $rememberDuration);
+	}
+
 	/**
 	 * Validates an email address
 	 *