Mercy Wanjiku Njoroge (born 10 June 1986) is a Kenyan long-distance runner who specialises in the steeplechase.

She claimed the steeplechase title at the 2005 African Junior Athletics Championships.

Moving into the senior ranks, at the 2006 World Cross Country Championships she finished twelfth in the long race, helping the Kenyans to the silver medal in the team competition.

Njoroge won the silver medal in the steeplechase behind Milcah Chemos Cheywa at the 2010 Commonwealth Games in New Delhi.

She opened her 2011 season with an indoor 3000 m best of 8:50.32 minutes to win at the Sparkassen Cup.