Characteristics of English for Academic Purposes students' second language (L2) motivation were examined by identifying underlying motivational factors. Using the motivation constructs created by first language reading researchers, a survey was developed and administered to 2,018 students from 53 English language programs in the U.S. Survey responses were analyzed through exploratory and confirmatory factor analyses. Results indicate that a five-factor structure was best for interpreting the data, accounting for approximately 44% of the total variance. The identified factors included one intrinsically-oriented factor (Intrinsic Motivation) and four extrinsically-oriented factors (Drive to Excel, Academic Compliance, Test Compliance, Social Sharing). The results support the multidimensional nature of L2 reading motivation and the importance of intrinsic motivation in explaining L2 reading motivation. (Contains 9 tables.)