Abstract: Disclosed is an expansion joint guide for constructing a multi-course masonry block wall. The guide has an elongated flat planar base of a rigid material and an elongated planar leg the length of which is less than the thickness of the blocks of the wall to be constructed and the thickness of which is the desired thickness of the joint between laterally adjacent blocks of the wall. The leg extending substantially perpendicular to the base to serve as a locator for the masonry blocks forming the sections of the wall on either side of the guide and means preferably in the form of fasteners or adhesives are used to secure the base to an underlying wall.