John Southern Spencer (born 10 August 1947) is a former England international rugby union player. He was born in Grassington, Yorkshire, in 1947 and educated at Cressbrook, Sedbergh School, and Queens' College, Cambridge. He has three children, David, Hazel and Emily.
Spencer played for Cambridge in the Varsity Matches of 1967, 1968 and 1969. He played club rugby for Headingley as a centre and made his England debut at the age of 21 against Ireland at Lansdowne Road, Dublin, in February 1969. He went on to play 14 times for England, scoring 2 tries. His last game was against the President's Overseas XV in a Rugby Football Union centenary match at Twickenham in April 1971. He captained England in four internationals.
Spencer was selected for the 1971 British Lions tour to New Zealand and played in ten matches on the tour but he did not appear in any of the four test matches against the All Blacks. He also represented the Barbarians.
He is now head of Club England which is part of the RFU as well as President of the Wharfedale R.U.F.C. in Grassington.
Spencer is currently tour manager for the British and Irish Lions on their 2017 tour to New Zealand.