Abstract: The present application discloses an adjustment assembly and a headrest. The adjustment assembly includes: a guiding rod; a fixing member, fixed to an end of the guiding rod; a driving portion, movably connected to the fixing member; and a first screw, engaged to the fixing member with threads, and the driving portion is connected to the fixing member by the first screw, wherein the driving portion includes a first motor, and the first motor is used to drive the driving portion to linearly move in respect to the fixing member along a direction close to or away from the fixing member. The adjustment assembly of the application can be adjusted electrically, such that the operation is convenient, and the structure is simple and reliable.