In 2009, staff at Canada's Mental Health Commission's Opening Minds antistigma initiative implemented a multiplatform social marketing campaign to test its feasibility and effectiveness in changing public stigma. Media platforms included newspapers, television, and social networking. The content was designed to speak to the average Canadian by putting a face to mental illnesses, featuring case studies of real people who had experienced mental health challenges. The evaluation collected precampaign and postcampaign data from a national subsample of media-engaged individuals who were drawn from a marketing research platform (n = 4,000)-a subsample of the population that was considered most likely to show change. Results did not show statistically significant improvements in campaign awareness, stigma-related knowledge, attitudes, or intended behaviors, and there was no discernible pattern to suggest that postcampaign items were uniformly moving in the desired direction. Our inability to increase campaign awareness from baseline to postcampaign is the likely explanation for our lack of effect. The total cost of the campaign was estimated to be over 1.5 million Canadian dollars. Given the lack of improvement in campaign awareness and impact and the prohibitively high cost, the program pivoted to target specialized groups in the media, workforce, health care, and schools. Possible reasons for the lack of campaign awareness are discussed.