In sex education, traditional teaching approaches that place the teacher in the centre of learning provide little opportunity for promoting the development of students’ sexual knowledge, maturity, self-confidence, communication skills, and well-rounded personalities. In Thailand, this traditional approach has an impact on teenage students’ effective learning for the Comprehensive Sex Education (CSE) curriculum through their behaviours and attitudes about sex-related topics. Moreover, CSE does not cover many approaches such as discussions and debates to promote students’ analytic and critical-thinking skills related to sexual-related topics. (MSDHS, 2019 ; UNESCO, 2021 & UNICEF, 2016). This study investigates students' learning CSE through embedded digital Games-Based Learning (GBL) module that is delivered to Grade 7 (age 12-14) secondary school students in the north of Thailand. Researchers in this study developed a game that aims at encouraging and stimulating students’ skills to analyse and critique their understanding of CSE. The purpose of this paper is to investigate how the levels of Bloom’s Taxonomy have been manifested with students’ learning using GBL. In the course of the study, 1152 students responded to answer pre and post-tests. The statistical findings show that students’ scores in the post-test were significantly higher than those of the pre-test (withought GBL). This paper concludes that, GBL facilitated opportunities for students to conceptualize, apply, analyse, synthesize, evaluate and create their learning actively and skilfully. However, the statistical data highlights that the development measured after the use of CSE gamified syllabus does not occur at the same rate and that some skills developed at a higher rate than others. Importantly, the study found that GBL is not a standalone approach to teach CSE, other pedagogical approaches (e.g., enquiry-based learning) need to be embedded. These approaches can be implemented with or without technology, but they need to be planed ahead. Final study conclusion is that, efficient teaching of CSE is not down to students only, collective efforts of other stakeholders (e.g., parents, policy makers, etc), are needed.