Maunawili (Hawaiian pronunciation: [mɐwnəˈvili]) is a residential census-designated place (CDP) in the City & County of Honolulu, Koʻolaupoko District, Island of Oʻahu, Hawaii, United States.

Situated mauka (inland or mountain side) of Kalanianaʻole Highway between Castle Junction and Castle Hospital, Maunawili is nearly all private homes, schools, and a few churches; horse stables complete the rural setting.

The residential developments extend only part way back into the valley, which is quite large and fairly wet, supporting limited agriculture (mostly banana growing) behind the housing.

Water from the numerous streams is diverted by a ditch to much drier Waimānalo to support agricultural activities there.

The agriculture research station is also home to a sugar cane, coffee and cacao breeding program.

An attraction of increasing popularity is the Maunawili Demonstration Trail, a state-maintained trail that traverses the breadth of upper Maunawili Valley from the Pali Highway (access at the "Horseshoe Curve") to Waimānalo.

According to the United States Census Bureau, the CDP has a total area of 1.9 square miles (4.8 km2), all land.

The Hawaii Department of Public Safety operates the Women's Community Correctional Center in what was the Maunawili CDP as of the 2000 U.S.