This study is to develop and validate a scale that measures the acceptance intention of secondary school teachers toward gamified English-as-a-foreign-language (EFL) tools. Drawing upon the technology acceptance models (TAM) and related frameworks, we synthesized a framework that includes six main factors contributing to teachers' acceptance intention of gamified learning tools. These factors are perceived enjoyment, perceived usefulness (PU), perceived ease of use (PEoU), perceived risks, facilitating conditions, and control variables. The study involved 361 and 512 secondary school teachers who participated in qualitative interviews and quantitative surveys, respectively. Surprisingly, in the context of implementing gamified tools for the teaching of English-as-a-second-language, the results indicate that only two factors can be retained in the proposed framework (PU and PEoU). However, PU and PEoU in the current research contexts brought new connotations, which is of significance for future studies. Eventually, a five-item scale measuring PU (PU-gamification-EFL) and a six-item scale measuring PEoU (PEoU-gamification-EFL) have been validated. Implications and limitations were discussed, as well as suggestions for future studies.