Onèsphore Nkunzimana (born July 23, 1985 in Burundi) is a male long-distance runner His first major competition was the 2000 World Junior Championships in Athletics, where he finished ninth in the 5000 metres He switched from Burundi to represent Qatar and adopted a new name Sultan Khamis Zaman while competing for them.

He finished eighth in the short race at the 2004 IAAF World Cross Country Championships and won a team silver medal with Qatar.

He took the 3000 metres gold medal at the 2008 Asian Indoor Athletics Championships.

He represented Qatar at a major competition for a final time at the 2008 Beijing Olympics, but he did not progress beyond the heats.

This biographical article relating to Qatari athletics is a stub.