The 2013 Isle of Man TT Races were held between the Saturday 25 May and Friday 7 June 2013 on the 37.73-mile Isle of Man TT Mountain Course in the Isle of Man. The event celebrated the 90th anniversary of the first Sidecar TT with a special parade lap for racing sidecar outfits. The 2013 Isle of Man TT Festival also included the Pre-TT Classic Races on 24, 25 & 27 May 2013 and the Post-TT Races on 8 June 2013 and both events held on the Billown Circuit.

The Senior Tourist Trophy is a motorcycle road race that takes place during the Isle of Man TT festival, an annual event traditionally held over the last week in May and the first week in June. The Senior TT is the blue ribbon event of the festival that takes place on the Friday of race week, with "The Marquis de Mouzilly St. Mars trophy" awarded to the winner.