The purpose of this study was to investigate the decisions of civil servants to use Web 2.0 applications while engaging in online learning. The participants were 439 civil servants enrolled in asynchronous online learning programs, using an e-learning portal provided by Taiwan's Regional Civil Service Development Institute. The participants completed a questionnaire which measured their responses to 12 constructs (perceived usefulness, perceived ease of use, compatibility, peer influence, superior influence, self-efficacy, facilitating conditions, attitude, subjective norm, perceived behavior control, behavior intention, and behavior) based on the decomposed theory of planned behavior. The research results revealed that the participants' perceived usefulness of online learning was the strongest predictor affecting their attitude. Peer influence was also the primary factor influencing their subjective norm. The construct of self-efficacy appeared to be the most important element determining their perceived behavioral control. Also, the results of the path analysis showed that the participants' attitude was the strongest indicator of their behavior intention to use Web 2.0 applications, followed by the perceived behavior control and subjective norm. Theoretical and practical implications and recommendations are provided based on the results of the study.