A derailleur comprises a base member, a chain guide, and a linkage structure. The linkage structure includes a first link pivotally coupled to the base member about a first link pivot axis. The chain guide includes a first chain guide pivotally coupled to the first link about a first guide pivot axis spaced apart from the first link pivot axis. The first chain guide includes a first guide body and a first guide protrusion. The first guide protrusion protrudes from the first guide body and is pivotally coupled to the first link about the first guide pivot axis. The first guide protrusion is spaced apart from the first link in an axial direction with respect to the first guide pivot axis to define an intermediate space between the first guide protrusion and the first link in the axial direction. The intermediate space is free of a spring.