The Mannin Moar was a non-championship Grand Prix held in Douglas, Isle of Man, Great Britain in 1933, 1934 and 1935.

However, the Isle of Man had its own laws, so a racing circuit was designed on the streets of Douglas.

Two races were organised, Mannin Beg (English: Small Man) for non-supercharged voiturettes with engines smaller than 1500cc on 12 July 1933 [1] and Mannin Moar (English: Great Man) for cars with engines over 1500cc and supercharged voiturettes on 14 July 1933.

On behalf of the drivers, Earl Howe wrote a letter to The Motor complaining that the rules were considered an embarrassment and would turn races from international events into second rate affairs.

The start line of the original track was near the Villa Marina on the Douglas Promenade.