diff --git a/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/devices_table.go b/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/devices_table.go
index 65112cd84..62932b65f 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/devices_table.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/devices_table.go
@@ -57,13 +57,18 @@ const selectDeviceByTokenSQL = "" +
 const deleteDeviceSQL = "" +
 	"DELETE FROM device_devices WHERE device_id = $1 AND localpart = $2"
 
+const deleteDevicesByLocalpartSQL = "" +
+	"DELETE FROM device_devices WHERE localpart = $1"
+
 // TODO: List devices?
 
 type devicesStatements struct {
-	insertDeviceStmt        *sql.Stmt
-	selectDeviceByTokenStmt *sql.Stmt
-	deleteDeviceStmt        *sql.Stmt
-	serverName              gomatrixserverlib.ServerName
+	insertDeviceStmt             *sql.Stmt
+	selectDeviceByTokenStmt      *sql.Stmt
+	deleteDeviceStmt             *sql.Stmt
+	deleteDevicesByLocalpartStmt *sql.Stmt
+
+	serverName gomatrixserverlib.ServerName
 }
 
 func (s *devicesStatements) prepare(db *sql.DB, server gomatrixserverlib.ServerName) (err error) {
@@ -80,6 +85,9 @@ func (s *devicesStatements) prepare(db *sql.DB, server gomatrixserverlib.ServerN
 	if s.deleteDeviceStmt, err = db.Prepare(deleteDeviceSQL); err != nil {
 		return
 	}
+	if s.deleteDevicesByLocalpartStmt, err = db.Prepare(deleteDevicesByLocalpartSQL); err != nil {
+		return
+	}
 	s.serverName = server
 	return
 }
@@ -110,6 +118,14 @@ func (s *devicesStatements) deleteDevice(
 	return err
 }
 
+func (s *devicesStatements) deleteDevicesByLocalpart(
+	ctx context.Context, txn *sql.Tx, localpart string,
+) error {
+	stmt := common.TxStmt(txn, s.deleteDevicesByLocalpartStmt)
+	_, err := stmt.ExecContext(ctx, localpart)
+	return err
+}
+
 func (s *devicesStatements) selectDeviceByToken(
 	ctx context.Context, accessToken string,
 ) (*authtypes.Device, error) {
diff --git a/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/storage.go b/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/storage.go
index ea7d87383..c100e8f58 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/storage.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/auth/storage/devices/storage.go
@@ -109,3 +109,17 @@ func (d *Database) RemoveDevice(
 		return nil
 	})
 }
+
+// RemoveAllDevices revokes devices by deleting the entry in the
+// database matching the given user ID localpart.
+// If something went wrong during the deletion, it will return the SQL error.
+func (d *Database) RemoveAllDevices(
+	ctx context.Context, localpart string,
+) error {
+	return common.WithTransaction(d.db, func(txn *sql.Tx) error {
+		if err := d.devices.deleteDevicesByLocalpart(ctx, txn, localpart); err != sql.ErrNoRows {
+			return err
+		}
+		return nil
+	})
+}
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/logout.go b/src/github.com/matrix-org/dendrite/clientapi/routing/logout.go
index ff214fe57..d03e7957f 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/logout.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/logout.go
@@ -50,3 +50,22 @@ func Logout(
 		JSON: struct{}{},
 	}
 }
+
+// LogoutAll handles POST /logout/all
+func LogoutAll(
+	req *http.Request, deviceDB *devices.Database, device *authtypes.Device,
+) util.JSONResponse {
+	localpart, _, err := gomatrixserverlib.SplitID('@', device.UserID)
+	if err != nil {
+		return httputil.LogThenError(req, err)
+	}
+
+	if err := deviceDB.RemoveAllDevices(req.Context(), localpart); err != nil {
+		return httputil.LogThenError(req, err)
+	}
+
+	return util.JSONResponse{
+		Code: 200,
+		JSON: struct{}{},
+	}
+}
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go b/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
index 0b9e4172a..04c183f32 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
@@ -160,6 +160,12 @@ func Setup(
 		}),
 	).Methods("POST", "OPTIONS")
 
+	r0mux.Handle("/logout/all",
+		common.MakeAuthAPI("logout", deviceDB, func(req *http.Request, device *authtypes.Device) util.JSONResponse {
+			return LogoutAll(req, deviceDB, device)
+		}),
+	).Methods("POST", "OPTIONS")
+
 	// Stub endpoints required by Riot
 
 	r0mux.Handle("/login",