Purpose: The psychological theory of self-determination postulated that gamification enhances learning engagement by intrinsically motivating learners to undertake tasks spontaneously. Gamification has then been integrated into adult learning as part of the initiative of learner-centred pedagogies to curb the low retention rates of adult learners who struggle with heavy work commitments, family obligations and financial pressure. Gamification, being one of the technological mediations, assumes the crucial role of engaging and retaining adult learners. Adult learners have received less attention in research when compared with conventional university students. The purpose of this study is to conduct a bibliographic analysis to assess the past, present and future publication trends of gamifying adult learning and to identify the research gap. Design/methodology/approach: This study included publications related to gamification and adult learning from 2014 to 2022, extracted from Dimensions. A total of 79,864 publications were retrieved initially, and 3,469 publications were ultimately selected for final analysis after the refinement of the keyword search. VOSviewer was used for bibliographic coupling, keyword co-occurrence, clustering and co-citation analysis of countries. Findings: The number of publications related to gamification in adult learning has decreased since its peak in 2020. The saturation is mainly concentrated in the USA, the UK and China, with similar levels of national income and technology advancement skills. However, gamification in adult learning remains a popular and growing research area in developing countries like Malaysia, which has huge potential due to government investments in education, technology and lifelong learning. There is also an evident research gap on gamification, adult learning and personality traits, which have not been covered in previous studies. Originality/value: Prior research mostly focused on systematic literature reviews, while the use of bibliometric analysis could be a missing link in this research domain. This paper unveils the evolution of publications on this topic over time by scientifically analysing a large number of publications and rigorously identifying research gaps contributing to future research avenues.