William Augustine Whelan (born 1 April 1935 in Dublin – 6 February 1958), also known as Billy Whelan or Liam Whelan, was an Irish footballer and one of the eight Manchester United players who were killed in the Munich air disaster. He was 22 years old when he died.

Whelan came from a large family; his father John had died in 1943, when Whelan was eight years old. He was not a confident flyer and just before the aeroplane took off from Munich, he was heard to say: "Well, if this is the time, then I’m ready."

Whelan began his career with Home Farm before joining Manchester United.

He made 98 first-team appearances in four seasons at United, scoring 52 goals. He was United's top scorer in the 1956-57 season, scoring 26 goals in the First Division and 33 in all competitions as United won their second successive league title and reached the semi-finals of the European Cup and FA Cup.

He had previously played for Irish club Home Farm, and was capped four times for the Republic of Ireland national team, but unfortunately did not score.

His brother John played for Shamrock Rovers and Drumcondra F.C..

On 8 December 2006 the railway bridge on Fassaugh Road/Dowth Avenue junction in Cabra, Dublin 7 close to Dalymount Park was renamed in his honour. The campaign to have the bridge renamed was initiated and organised by members of the Cabra, GAA club, Naomh Fionbarra (gaelic spelling) (St. Finbarr's) and sanctioned by Dublin City Council in early 2006. It is close to St. Attracta Road, the street in which he was born. The unveiling ceremony was performed by Whelan's Manchester United team mate at the time of the aircrash, Sir Bobby Charlton.

On 4 February 2008, the Irish national postal body An Post issued a 55c postage stamp for the 50th anniversary of the Munich Air Disaster showing a photo of Liam Whelan.

Whelan is buried in Glasnevin Cemetery.