A timing belt spacer tool with an arcuate spacer portion of predetermined uniform thickness and an extension tab extending in an axial direction from the mid-section of the spacer portion. The extension tab may have a grip, which may be in the form of a protrusion, bulge, thickness variation, edging, bead, or the like. The opposing ends of the arcuate spacer portion may be flexible enough to be straightened in use but still return to their original arcuate shape.