diff --git a/src/users.rs b/src/users.rs
index 3b34b6a..f4838b6 100644
--- a/src/users.rs
+++ b/src/users.rs
@@ -5,6 +5,7 @@ pub mod get_details;
 pub mod is_user_admin;
 pub mod list_joined_rooms;
 pub mod list_users;
+pub mod login_as_a_user;
 pub mod reset_password;
 
 use ruma::{thirdparty::ThirdPartyIdentifier, SecondsSinceUnixEpoch};
diff --git a/src/users/login_as_a_user.rs b/src/users/login_as_a_user.rs
new file mode 100644
index 0000000..22d64e2
--- /dev/null
+++ b/src/users/login_as_a_user.rs
@@ -0,0 +1,3 @@
+//! Different versions of the endpoint to log in as a user.
+
+pub mod v1;
diff --git a/src/users/login_as_a_user/v1.rs b/src/users/login_as_a_user/v1.rs
new file mode 100644
index 0000000..02a5435
--- /dev/null
+++ b/src/users/login_as_a_user/v1.rs
@@ -0,0 +1,47 @@
+//! [POST /_synapse/admin/v1/users/:user_id/login](https://matrix-org.github.io/synapse/latest/admin_api/user_admin_api.html#login-as-a-user)
+
+use ruma::{
+    api::{metadata, request, response, Metadata},
+    UserId,
+};
+
+const METADATA: Metadata = metadata! {
+    method: POST,
+    rate_limited: false,
+    authentication: AccessToken,
+    history: {
+        unstable => "/_synapse/admin/v1/users/:user_id/login",
+    }
+};
+
+#[request]
+pub struct Request<'a> {
+    /// User to log in as.
+    #[ruma_api(path)]
+    pub user_id: &'a UserId,
+
+    /// Optional: Integer UNIX timestamp in milliseconds for when the access token should expire.
+    /// If not specified, the returned access token does not expire.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub valid_until_ms: Option<u64>,
+}
+
+#[response]
+pub struct Response {
+    /// An opaque access token string, that can be used to control the user.
+    pub access_token: String,
+}
+
+impl<'a> Request<'a> {
+    /// Creates an `Request` with the given user ID.
+    pub fn new(user_id: &'a UserId, valid_until_ms: Option<u64>) -> Self {
+        Self { user_id, valid_until_ms }
+    }
+}
+
+impl Response {
+    /// Creates a `Response` with the given admin flag.
+    pub fn new(access_token: String) -> Self {
+        Self { access_token }
+    }
+}