A child safety seat includes a seat shell having a backrest portion and a sidewall protruding forward from the backrest portion, an adjustable headrest movable along the backrest portion, and a first belt guide fixedly connected with the sidewall at a top thereof and a second belt guide provided on the headrest, wherein the first belt guide and the second belt guide are configured to receive a shoulder belt portion of a vehicle seatbelt disposed through a gap between the sidewall and the headrest. In some embodiments, the child safety seat may include a latch belt disposed transversally across the seat shell and having two opposite ends respectively provided with two connectors for attachment to an anchorage provided in a vehicle, and a storage compartment on a rear of the backrest portion adapted to receive the two connectors of the latch belt.