|1991 Australian Indoor Championships|
|Date||30 September - 7 October|
|Draw||64S / 32D|
|Prize money||$750,000 [a]|
|Surface||Hard / indoor|
|Venue||Sydney Entertainment Centre|
|Jim Grabb / Richey Reneberg|
The 1991 Australian Indoor Championships, also known by its sponsored name Uncle Toby's Australian Indoor Tennis Championships, was a men's tennis tournament played on indoor hard courts at the Sydney Entertainment Centre in Sydney in Australia and was part of the Championship Series of the 1991 ATP Tour. It was the 19th edition of the tournament and was held from 30 September through 7 October 1991. First-ranked Stefan Edberg won the singles title.