This study addresses key gaps in the positive psychology literature: one is the scarcity of studies involving high-ability students and those comparing the effects of positive psychology interventions (PPIs) with different foci--self and others-- on student outcomes. This study aimed to develop and evaluate the effectiveness of self-focused and others-focused PPIs on gratitude, wellbeing and relatedness of high-ability students. The self-focused PPI involved self-awareness and self-reflection activities while the others-focused PPI featured gratitude activities. The participants in the study were 246 high-ability students. The study applied a randomized controlled experimental design involving two experimental groups, which carried out either other-focused (n=123) or self-focused activities (n=46); and one control group (n=77), which carried out usual homeroom activities for one hour each week for 6 weeks. Surveys on students’ gratitude, wellbeing. school resilience and relatedness were administered at three time points: one week before, one week after and two-months after the intervention activities were completed by the students. Compared to the control group, the students who participated in the other-focused PPI showed small to moderate significant improvements in gratitude, wellbeing (i.e., life satisfaction), school resilience and relatedness with significant others, especially among students with low to moderate levels of baseline gratitude. Compared with the control group, students who took part in the self-focused PPIs showed only negligible gains in gratitude, wellbeing, school resilience and relatedness. The students’ written feedback regarding the activities were overwhelmingly positive, with the dominant themes in others-focused PPIs being the cognitive, effective and social benefits the activities. On the other-focused PPIs, the majority of the student’ responses were emotion-focused. Overall, the others-focused PPI appear to be more effective than the self-focused PPI in promoting wellbeing and relatedness of high-ability students.