A motor assembly for compressing a fluid by causing a rotational shaft to reciprocate by providing a drive force to the rotational shaft, and a reciprocating compressor including a motor assembly are provided. The motor assembly may include a cylinder block in which a bore is formed and which is penetrated by the rotational shaft, a stator coupled to the cylinder block, a rotor installed at an outer circumferential surface of the stator so as to be rotated by the stator and which is coupled to the rotational shaft so as to rotate together with the rotational shaft, and at least one fastening member that fastens the stator and the cylinder block to each other such that the stator is supported by the cylinder block.