Background: A key objective of government and social marketers is to remove the institutionalized stigma of mental illness, increasing mental health service uptake. While research has evaluated past campaigns based on changes in attitudes and beliefs, very little research has examined the communication messages used in social marketing campaigns. Focus of the Article: This impact evaluation research identifies the institutionalized cultural-moral norms incorporated into New Zealand’s Like Minds mental health advertisements and examines how attitudes and beliefs changed over time in response to these norms. Importance to the Social Marketing Field: This research offers a new approach to social marketing evaluation and demonstrates the importance of consistent incorporation of cultural-moral institutional norms in social marketing campaigns. Method: Using macro-social marketing theory, thematic analysis is used to identify the cultural-moral institutional norms in the Like Minds campaign advertisements over a 10-year period (2002–2012). Results: The Like Minds campaign was found to have multiple cultural-moral institutional norms, such as Mental illness as a villain, Personal responsibility, and Inherent human dignity, as well as utilizing two different institutionalization processes of Socialization and Identity Formation. However, these norms were inconsistently and sometimes contradictorily presented and as a result, not all changes in mental health stigma beliefs and attitudes show long term change. Rates for service uptake also had mixed results during the campaign duration, though overall an increase in uptake was found. Recommendations for Research and Practice: The research highlights the importance of understanding the underlying institutionalized cultural-moral norms presented in communications and aligning those with the overall objectives of a social marketing campaign. Limitations: Like Minds campaign phases 2 to 5 are analyzed, phase 1 was inaccessible for analysis and advertisements after 2012 are not analyzed.