The purpose of the study was to investigate factors that predict preservice teachers' intentions and actual uses of Web 2.0 tools in their classrooms. A two-phase, mixed method, sequential explanatory design was used. The first phase explored factors, based on the decomposed theory of planned behavior, that predict preservice teachers' intentions to integrate Web 2.0 tools in their future classrooms. The second, follow-up phase, explored preservice teachers' transfer of intentions into actions during student teaching and the factors that influenced actual use of Web 2.0 tools in their classrooms. Results of the study showed that perceived usefulness, self-efficacy, and student expectations were the strongest predictors of preservice teachers' intentions and actual use of Web 2.0 tools in the classroom. Additional findings revealed a significant positive relationship between preservice teachers' intentions and subsequent behaviors. The results of the second phase of the study showed that although most preservice teachers were able to carry out their intentions, due to facilitative factors, a few were unable to use Web 2.0 tools due to limited access to technology resources and unsupportive mentor teachers. These findings provide evidence that when preservice teachers perceive the value of Web 2.0 tools to facilitate student learning, have support from their K-12 students and mentor teachers, and have high self-efficacy as well as easy access to Web 2.0 tools, they are able to translate their intentions into actions.