The 1978 Belgian International Championships was a men's tennis tournament staged at the Leopold Club in Brussels, Belgium that was part of the Grand Prix circuit. The tournament was played on outdoor clay courts and was held from 12 June until 18 June 1978. It was the seventh edition of the tournament and unseeded Werner Zirngibl, who entered the competition as a qualifier, won the singles title.[1]
Werner Zirngibl defeated 
Ricardo Cano 1–6, 6–3, 6–4, 6–3
Antonio Zugarelli / 
Jean-Louis Haillet defeated 
Onny Parun / Vladimír Zedník 6–3, 4–6, 7–5