The 1991 Trans-Tasman Test series was an international rugby league test series played in Australia between Australia and New Zealand. The series, which started on 3 July in Melbourne and finished on 31 July in Brisbane, consisted of three test matches, with the third test doubling as a 1989–1992 Rugby League World Cup tournament match. New Zealand did not play in any other matches while on tour.
The test series was broadcast throughout Australia by the Seven Network with commentary provided by Pat Welsh, Roy Masters and John Harker. Paul Vautin provided sideline commentary during the first test in Melbourne but was replaced from the second test by Harker who moved to allow Wally Lewis to join the team following his omission from the Australian test team. Also doing sideline reporting during the series was John Brady.
The Australians, coached by Bob Fulton and captained by Mal Meninga, had come out of the successful 1990 Kangaroo Tour, while all players selected for the three Kiwi tests had recently participated in the 1991 State of Origin series, won by Queensland 2–1 over New South Wales (Queensland were actually coached by former Kiwi test coach Graham Lowe). Queensland captain Wally Lewis made his return to the test team for the first test at Olympic Park, after missing most of 1990 and all that year's tests with torn hamstring and later a broken right forearm. Lewis had been controversially ruled out of the Kangaroo Tour by team doctor Nathan Gibbs. Melbourne would prove to be his final test in the Green and Gold, Lewis being one of four players dropped from the side after the 8–24 loss to the Kiwis (second row forward Bob Lindner, voted as the player of the Kangaroo Tour, also missed the final two tests after breaking his leg at Olympic Park).