Billy MacKenzie (born 7 April 1984 in Edinburgh) is a Scottish former professional motocross racer.

[1] MacKenzie is a two-time British motocross national champion.

MacKenzie rode for the Honda factory racing team competing in the F.I.M.

[2] He has also represented the United Kingdom in the Motocross des Nations.

MacKenzie recorded his first and only World Championship victory when he won the MX-1 Class at the 2007 Japanese Motocross Grand Prix.