Lorong 21 Geylang is a minor road in Geylang, Singapore. It is segmented into two parts separated by Sims Avenue. The southern portion connects Geylang Road to Sims Avenue, with traffic flow one way from former to latter. Lorong Bachok forms a T-junction to it. The northern portion is presently a no-through road separated by the elevated railway of the East West Line, though it is possible to walk across to Sims Place.