Open badges are a digital representation of skills or accomplishments recorded in a visual symbol that is embedded with verifiable data and evidence. They are created following a defined open standard, so that they can be shared online. Open badges have gained popularity around the world in recent years and have become a standard feature of many learning management systems. This paper presents a systematic literature review of the published open badges literature from 2011 to 2015. Through database searches, searching the internet and chaining from known sources, 135 relevant peer-reviewed papers were identified from a corpus of 247 publications for this review. The authors believe this to be the first effort to systematically review literature relating to open badges. The review categorised publications while also providing quantitative analysis of publications according to publication type, year of publication and contributors. After assessing the literature suggestions for future research directions are presented, based on underrepresented areas.