Abstract: A portable tennis net post-supported tennis ball-throwing device including an elongated support member with a U-shaped clamp for attaching the support member in an upright orientation to an upright tennis net support post. An elongated rigid throwing rod is pivotally connected at one end portion thereof to the support member by a pivotal connection therebetween. An elongated elastic actuator member is connected to and extends between the support member and the throwing rod at respective positions on the support member and the throwing rod spaced from the pivotal connection. A tennis ball holding member is connected adjacent a distal end of the throwing rod and opens toward the support member to receive a tennis ball placed therein. A resilient stop member is connected to the support member to make contact with the throwing rod as it accelerates toward a final position thereof by the stretched actuator member.