This study aimed to understand the factors that deter immigrants from participating in Korean language programs in South Korea by finding the underlying structure of the deterrents. A new instrument with 39 items that measures adult immigrants' deterrents to participation in Korean language programs was developed. In total, 267 responses were collected, and 170 complete useable responses were analyzed. A series of statistical analyses revealed that the lack of time was the most compelling reason for nonparticipation. In addition, three latent dimensions of deterrents to participation were discovered: negative attitudes, social isolation, and competing demands. The factors were compared with the findings from previous research and implications for theory and practice were suggested.