The Glamorgan County Silver Ball Trophy (also known as the Glamorgan County High Motive Silver Ball Trophy) is a Welsh rugby union competition open to all non-premier Welsh Rugby Union (WRU) clubs playing in the Glamorgan area.

[1] The Silver Ball competition was suggested by Glamorgan County president Glan Williams in 1955.

The idea was to match eight junior teams against the county's eight first class sides, but a poor response from the senior teams resulted in the Welsh Academicals being drafted in to make a realistic quarter finals.

[1] The tournament also produces the SA Brains trophy which is awarded to the team to have scored the most tries during the buildup to the final.

This team is then invited to play the Silver Ball winners in a pre-season friendly for the President's Cup.