This study assessed students’ satisfaction with Ramkhamhaeng University regional library services (RURLs) and the perceived quality of information retrieved from other information sources. In particular, this study investigated factors relating to regional students’ selection of information sources to meet their information needs. The researcher applied the principle of least effort and Simon’s satisficing theory for this study. The former principle governs and predicts the selection of these students’ perceived source accessibility, whereas the latter theory explains the selection and use of the information retrieved without considering whether the information is optimal. This study employed a web-based survey to collect data from 188 respondents. The researcher found that convenience and ease of use were the top two variables relating to respondent’s selection of information sources and use. The Internet had the highest mean for convenience. Results of testing a multiple linear regression model of all four RURCs showed that these four independent variables (convenience, ease of use, availability, and familiarity) were able to explain 69% of the total variance in the frequency of use of information sources. Convenience and ease of use were able to increase respondents’ perceived source accessibility and explain the variance of the frequency of use of sources more than availability and familiarity. These findings imply that respondents’ selection of information sources at the RURCs were governed by the principle of least effort. Libraries could consider the idea of one-stop services in the design of the Web portal, making it user friendly and convenient to access. Ideally, students could have one card to check out materials from any library in the resources sharing network.