A basketball sports whistle having an integral basketball possession indicator at the eye level of the referee enables the referee to accurately determine which team is entitled to possession of the basketball without diverting his eyes from the basketball court. The referee switches the indicator to record a change of ball possession. A friction or detent lock in the integrally constructed indicator prevents the ball possession indicator from being accidentally switched to a different position. The possession indicator element is a friction lock slider, or a pop-up indicator in a see-saw like element with friction or a detent at the axis of the see-saw. It can alternatively be or a single pop-up element that carries either H for home team basketball possession or V for visitor team basketball possession.