Joseph Mwengi Mutua (born 10 December 1978 in Machakos, Eastern Province) is a Kenyan runner who specializes in the 800 metres.
His personal best time is 1:43.33 minutes, achieved in August 2002 in Zürich. He holds the African indoor record in 800 m with 1:44.71 minutes, achieved in January 2004 in Stuttgart.
He twice competed at the Summer Olympics. In 2000 he failed to advance 800 metres heats, but was part of the Kenyan 4*400m relay team that reached semifinals. At the 2004 Summer Olympics he reached 800 metres semifinals.
He won the Kenyan national championships in 2002, 2003 and 2004.
He was part of the 4 × 800 m relay team who currently holds the world record.