In this paper, an online self-evolving fuzzy controller is proposed for an autonomous leader/follower. The self-evolving controller starts with a simple configuration and learns from its own actions while controlling the mobile robot during the leader following behaviour. A traditional Takagi-Sugeno type fuzzy controller is also implemented and compared with the proposed controller to verify the reliability and performance of the self-evolving controller. Experiments are carried out with a real mobile robot Pioneer 3DX at Lancaster University.