Writing is one of the essential skills that EFL students, specifically in Thailand, need to achieve while their learning English during tertiary education. However, Thai EFL students have few chances to practice writing skills while learning. This study was conducted to develop an instructional design model for assisting students in learning collaboratively using Facebook groups to enhance their English writing skills at the beginning stage of their university education. In this study, collaborative learning and writing, the theory of instructional design, and five previous instructional design models were analyzed, and synthesized. In addition, the seven steps model for designing an instructional model by Brahmawong and Vate-U-Lan (2009) was adapted to develop the instructional design model. Experts in the fields of technology and English Language Teaching then evaluated the model. The results of the study showed that the elements of the FBCL Model was satisfactory and appropriate for giving EFL writing instruction in Facebook groups. The FBCL Model may also be beneficial in providing an instructional framework to EFL writing instructors and instructional designers.