The western flower thrips, Frankliniella occidentalis (Pergande), is a serious pest on agricultural crops. It was found in Taiwan affecting bell peppers, tomatoes, and ornamental plants. The occurrence of this invasive species restricted in Rei-ai Township in Nantou and Heping District in Taichung of central Taiwan, only in areas with elevators higher than 1,200 m. Official control is being conducted to prevent its spread. Adaptation of this thrips in Taiwan and its coexistence or competition with local thrips such as F. intonsa (Trybom) and Scirtothrips dorsalis Hood are worth of future investigation.