ASUB Rugby Waterloo is a Belgian rugby union club currently competing in the Belgian Elite League.

The club is based in Waterloo in the Walloon Brabant province of Belgium.

The official colours of the club are a combition of dark and marine blue.

The club was founded in 1959 and has won the Belgian Elite League title on 15 occasions most recently in 2013 and have won the Belgian Cup twelve times.

Along with Boitsfort RC they have dominated Rugby Union in Belgium but have not managed to match their previous successes over the last decade.