Adolescents in Hong Kong have become more liberal and receptive towards sex in recent decades. Research findings indicated an increase in the rate of premarital sex among Hong Kong adolescents. They also held a more permissive attitude towards premarital sex than in the past. Sex education, however, is not always well organised and delivered in schools. A recent survey indicated that Hong Kong teachers found themselves not well equipped to teach the sex education and lacked relevant learning and teaching resources. Current educational resources for sex education are mainly designed to be used in classroom. They are typically composed of presentation slides and lesson plans of group based activities. As discussion on sex is still taboo in Chinese society, self-learning resources can supplement classroom teaching. Unfortunately they are rarely offered online or tailored for mobile access. Available online resources are mostly text-based and are unattractive to the most vulnerable adolescent group. This project aims to address this gap by developing an interactive game playable on Facebook, iPad and the web to educate and equip young adolescents with reliable knowledge and positive attitudes towards sex and relationship and life skills necessary for making wise decisions regarding love and sex in a fun way. The game, titled Making Smart Choices, consists of five mini-games, adopting a Chinese user interface, offering different scenarios where players exact their decisions in their chosen virtual characters and learn in the process. The mini-games aim to help young adolescents: to gain better self-understanding for establishing a healthy love relationship; to learn to set and maintain intimate boundaries; to understand about sexual impulse and considerations in deciding whether to have sex or not; to acquire safer sex knowledge including awareness of selfprotection, contraceptives, prevention of sexually transmissible diseases, and emergency contraception; and to be aware of available options and support services in case of unplanned pregnancies. To evaluate the effectiveness and acceptance of the game among young adolescents, a series of workshops and game sessions were conducted for more than 1,100 junior students ( in Secondary 1 to Secondary 3) in six co-ed secondary schools. Students' knowledge about safer sex was collected before and after playing the game. Participants were also asked to complete a questionnaire regarding their perception of the value of the game and whether they found the game interesting and user-friendly. Focus group interviews were arranged with selected students in order to gather their detailed feedback. The collected data were analysed using SPSS and the results showed that after playing the game, students' sex knowledge improved with a high medium effect size. The improvement was found in every junior secondary level. The survey respondents perceived that the game had helped them enhance their critical thinking, decision-making and ability to seek help regarding matters related to love and sexuality in addition to knowledge and proper attitudes towards relationship and sex. They were mostly receptive to the game, finding it fun to play with and describing the content as "interesting", "interactive", "informative", "close to reality" and "applicable".