This study explored the effects of need satisfaction (autonomy, competence, and relatedness) on English as a foreign language (EFL) online learner satisfaction and validated the Chinese versions of the need satisfaction scale (NSS) and online learner satisfaction scale (OLSS). We collected data from a questionnaire administered to 199 EFL students at a Taiwanese university. The Cronbach's alpha reliability coefficient for NSS was 0.90 and 0.91 for OLSS. For NSS, the principal component analysis (PCA) resulted in a three-factor solution that accounted for 61.31% of the variance. Regarding OLSS, PCA resulted in a two-factor solution that accounted for 63.17% of the variance. A multiple regression analysis revealed that three independent variables (autonomy, competence, and relatedness) were predictors of EFL online learner satisfaction (F(3, 191) = 85.14, P < 0.001, R[superscript 2] = 0.57), with competence the best predictor of online learner satisfaction, followed by relatedness and autonomy. The paper concludes with implications of these results.