A linear compressor includes a shell, a motor in the shell, a mover coupled to the motor and configured to perform a reciprocating motion in an axial direction, a cylinder disposed in the shell, a piston coupled to the mover and configured to reciprocate in the cylinder, a spring that supports the piston in the axial direction, and a spring cap inserted into an end portion of the spring. The spring cap defines a space portion that is defined inside the spring cap and has a volume separate from the inner space of the shell, and a passage portion that extends through an axial side surface of the spring cap and is configured to provide communication between the space portion and the inner space of the shell.