The olive fruit fly (Bactrocera oleae, Dacus oleae) is a species of fruit fly which belongs to the Dacinae subfamily. It is a phytophagous species, whose larvae feed on the fruit of olive trees, hence the common name. It is considered a serious pest in the cultivation of olives.

Until 1998, the fly had not been detected in the United States, and its range coincided with the range of the olive tree in the Eastern Hemisphere: northern, eastern and southern Africa, Southern Europe, Canary Islands, India, and western Asia. 

In the Western Hemisphere, it is currently restricted to California. The olive fruit fly was first detected in North America infesting olive fruits on landscape trees in Los Angeles County in November 1998. It can now be found throughout the state.[1] Its likely source of importation was from France.