Teachers' professional development (PD) receives a great deal of attention in current educational settings. However, research has shown that many teachers hesitate to attend PD programs. In this study, data were collected from 270 elementary school teachers and were subjected to confirmatory factor analysis and structural equation modeling to examine their intention to attend the weekly PD programs on Wednesday afternoons (PDWAP). The results revealed that the participants value the acquisition of pedagogical content knowledge (PCK) more than they value pedagogical knowledge (PK) and content knowledge (CK) because of the expected usefulness of each for teaching. Moreover, the results of this study have implications for PD program design, and call for a stronger focus on PCK.