Online gambling is emerging as a significant health behaviour of concern at a population level. Mobile applications (apps) are a popular tool to target change in health behaviour. Behaviour change techniques (BCTs) can be included within such apps to change relevant psychological mechanisms along established pathways, yet the content of apps targeting gambling problems specifically is not currently known. The purpose of the review was to identify the BCTs included in gambling prevention apps. Apps were downloaded from the Apple App Store and Google Play Store in October 2020. Apps were included if they related to gambling problems, were freely downloadable, and available in English. Once downloaded, two researchers independently coded the apps in November 2020 using the behaviour change technique taxonomy version 1 (Michie et al., 2013). The screening led to forty apps meeting the inclusion criteria (12 Apple App Store, 28 Google Play). The analyses identified 32 BCTs (20 Apple apps, 28 Google Play apps), with apps including between 0 and 9 BCTs (mean = 2.82, median = 2). The BCTs included most frequently were “3.1. Social support (unspecified),” “2.3. Self-monitoring of behaviour,” and “7.4. Remove access to the reward.” The review provides important information on the BCTs used in apps developed to reduce gambling-related problems. A limited number of BCTs were adopted within apps. Developers of apps seeking to develop effective gambling reduction products should draw upon a greater variety of BCTs.