A golf putting practice aid comprising a guide having a guide surface (3) with which a heel or the toe of a putter makes contact in use. The guide is positioned to extend upwardly from a substantially planar base or ground surface (1,100'). By making the guide surface straight throughout its length, and inclined towards the user, the surface will act to constrain the putter head to follow an inclined plane angled towards the user. By using a planar guide 3', a player can decide whether to have the toe or the heel of the putter guided thereby.