A golf putting practice aid has a rectangular base frame that serves as a stroke window for shot set-up and aiming purposes. A side frame is movably mounted on the base frame for pivotal movement from a folded, minimum profile storage configuration to an upright operative putting position. The side frame includes an elongated guide bar disposed in parallel alignment with the longitudinal axis of the stroke window for engaging and guiding pendulum movement of a putter shaft during execution of a putting stroke. The slope angle of the side frame relative to the base frame, and thus the elevation of the guide bar, is manually adjustable to suit the golfer's personal swing preference and putter selection. The guide bar and one of the base rails are marked with colored bands for indicating back swing stroke range and follow-through stroke range.