In Hong Kong, the curriculum reform of primary education has been embarked upon in the new century, followed by the change of the secondary school (SS) curriculum from six to seven years. Aligned with the 21st century skills, education reform aimed to prepare students with generic skills (e.g., collaboration and perspective-taking skills) and qualities (e.g., altruism) for the increasingly diverse and complex world. This study examined senior secondary (SS) students’ perceptions on the sources of formal and non-formal curricula influencing their cultivation of generic skills with particular reference to citizenship. The mixed-methods approach was used to provide a holistic view of students’ perceptions on the means through which formal and informal curricula cultivate their collaboration, altruism, and perspective-taking skills. Quantitative results indicated that 116 among 192 students thought they possess a high level of collaboration ability, while the qualitative findings corroborated that collaboration skills could be developed via various approaches. The quantitative results showed that among 52 students, 25 possessed a medium level of perspective-taking skills, whereas 23 rated themselves with high level. The qualitative results denoted that students’ views on formal curriculum (e.g., the subject of Liberal Studies) on fostering student perspective taking varied. The quantitative findings indicated that 19 among 31 students possessed a high level of “altruism” and the qualitative results explained their experiences associated with caring for others and altruism.