Despite significant progress, literacy programme implementation in Cambodia continues to face challenges concerning inactive learning participation, irregular attendance and dropout. Learners' motivation to engage in learning literacy, and the barriers that prevent them from doing so, are not adequately researched. This mixed-methods study aims to investigate learners' perceptions of what motivates them to participate in literacy learning and the barriers they face. The author conducted a survey with 256 adult literacy learners and interviewed 12 literacy teachers and 15 learners. The results show that learners' major motivations are to obtain literacy skills, help their children learn, become the family's role model, and develop themselves to gain a better standing in their community. Although male and female learners were motivated by similar factors, there was variation between those learning in factories and those learning in the community, and between urban and provincial learners. This indicates that, although learners had similar reasons for learning, certain reasons stood out as the most important. Barriers to learning included lack of time, family burdens, and negative views about learning. This study implies that understanding adults' contexts and learning motivation, organising flexible learning schedules and responsive learning content, and expanding literacy programmes to the workplace may contribute to reducing learning barriers, increasing participation, and bridging the gap between learning supply and demand.