This study investigated the effectiveness of a four session online teacher\u2019s development program on creating CALL teaching materials. The sessions were conducted through a synchronous computer-mediated video communication platform and set two learning outcomes; 1) fostering teachers\u2019 technological skill to create a computer-based teaching material, 2) building teachers\u2019 knowledge to evaluate the qualities of a Computer-Assisted Language Learning (CALL) material using the CALL appropriateness framework (Chapelle, 2001). The sessions were designed based on the project-based learning framework and TPACK-in-Action model. This case study collected the data through the screen captured videos, chat logs, teachers\u2019 reflection journals, teachers\u2019 final projects, and teachers\u2019 material evaluation skills demonstrated by the end of the TDP. The data were then analyzed qualitatively. The results showed that despite some significant time ineffectiveness and technical issues, the sessions successfully achieved the learning outcomes. Additionally, the teachers considered the overall sessions useful in developing their technical knowledge to develop CALL materials and assuring their quality. These results advocate for some technical supports from the institution and strong commitment of the participating teachers.<\/p>\n