The effectiveness of government health messages promoting influenza vaccination in Hong Kong was evaluated using content analysis of all the public service announcements deployed during 2010–2013. Threat appeals, normative appeals, message tone and message framing were analyzed. The results suggest that many messages were poorly tailored, loosely targeted and delivered too didactically. Most messages failed to present balanced information about influenza threats, the effectiveness and safety of vaccination, and self-efficacy to protect themselves and their families. The messages were too generally targeted, lacking proper target segmentation and ignoring certain high-risk groups. Implications for designing future influenza vaccination promotions are discussed.