The olive fruit fly (Bactrocera 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.

The problem is that much time and money are being spent, in order to determine whether the flies' population is large enough, so that pesticides should be sprayed on the trees.