Older adults are increasing dramatically throughout the globe. Due to this trend, learning has become an important pathway to improve older adults quality of life in many countries. The purpose of this study was to understand the intrinsic motivation of older adult learners in Taiwan. Older adult learners for this study are defined as learners over 65 years old. The three research questions guiding the study were: (a) what are the intrinsic motivations to learn for older adults in Taiwan? (b) to what extent can the intrinsic motivation to learn be explained by separated and combined personal predictor variables and institutional predictor variables of older adult learners in Taiwan? (c) to what extent are the relationships between personal predictor variables and intrinsic motivation to learn mediated by teacher support, peer support and/or family support?Three research questions were examined in this study using descriptive statistics, multiple regression and path analysis by using SPSS 19.0 and MPlus 6.0. In total, the sample population for this study was 816 older adult learners in Taiwan with an average age of 67.95. The respondents were 32.4% male and 67.6% female. The three major conclusions of this study were: (a) The intrinsic motivations of older adult learners are high; the most salient motivations for older adult learners are the desire for stimulation and generativity; (b) institutional predictor variables, especially teacher support and peer support, are the most important predictors of the intrinsic motivation of Taiwanese older adult learners; and (c) teacher support, peer support, and family support mediated the relationship between older adult learners personal characteristics and intrinsic motivation to learn.