This chapter aims to argue that there are two distinct kinds of head movement. One kind is triggered by morphological properties of the host head, while the other kind is not, and in fact often appears to be triggered by some property of the moved head. Adopting and extending the terminology of Chomsky & Lasnik, we refer to the former as L-related head movement and the latter as non-L-related head movement. Both types of head movement are subject to the ECP, but, since the nature of the target of movement is different in each case, the antecedent-government requirement manifests itself in different ways. The chapter proposes an analysis of clitic-climbing which treats this construction as a case of non-m-selected head movement. It shows that four constructions are related to AGR’s ability to head-govern the trace of non-m-selected, and possibly therefore, long, head movement: LHM, clitic-climbing, long infinitive-movement and Aux-to-Comp.