There is widespread acceptance of the benefits of social and emotional learning (SEL) curriculum in the educational context. However, the assessment of learning outcomes is not so clearly documented. This review compares SEL and the related constructs in three international settings, namely Australia, UK and USA, and then focuses on the assessment tools and practices used to examine SEL learning outcomes. To identify the assessment approaches used, multiple database searches were conducted. Boolean searches were conducted using the following terms: student, learning, assessment, resilience, perseverance, self-management, social emotional learning, personal, social capability, psychology of learning and learning outcomes. The database searches were limited to English-language scholarly articles in peer-reviewed journals published from January 1990 onwards. Eight key studies were examined in depth, which collectively reported on over 120 tools/instruments. Lessons learnt from these studies are detailed in the chapter. From the review, it is clear that there is no magic bullet for assessing SEL across all age groups. The choice of measures differs depending on the purpose of the assessment. In building an approach to assessment, there are eight key considerations that may be distilled from the literature. A number of suggestions are offered for future definition and assessment of SEL.