This study investigated the level of Video-Based Instruction (VBI) competency of Thai EFL teachers through training using the Video-Enhanced Language Teaching (VELT) model and examined their attitudes towards the training using the VELT model. The study group consisted of 30 secondary-level Thai EFL teachers with low VBI competency in Suphanburi province, Thailand, in the 2022 academic year. The study used mixed methods, and the data were collected using the achievement test and the assessment which were analyzed with a paired sample t-test to investigate the effects of the VELT model on developing the low VBI competency of Thai EFL teachers. The questionnaire data were analyzed using descriptive statistical analysis methods and the interview data using thematic analysis. The results showed that the VELT model had significantly improved the low VBI competency of Thai EFL teachers during the training period, showing a strong positive correlation (r =0.070, p <0.001). The assessment also indicated that Thai EFL teachers showed significant development in technology, pedagogy, and content related to English language teaching with a small positive correlation (r = 0.220, p <0.001) between their initial competency levels and the changes observed after training. The overall satisfaction towards the training using the VELT model was at a high level (M = 4.25) with the highest domain being the learning environment (M = 4.54). The interview revealed that interaction, learning environment, instruction, preference, obstacles, challenges, adaptation, preparation, and evaluation connected the use of the VELT model to ELT classes given by low VBI competency Thai EFL teachers. Four emerging data that stood out from the interview were the school's policy, materials, teaching styles, and students' motivation. The results have useful implications for the future implementation of videos for English language teaching.