The last few decades have seen growing concerns among parents regarding the safety of childhood vaccines, arguably leading to the rise of the anti-vaccine movement. This study is an effort to understand situational and cross-situational factors that influence individuals' negative attitudes toward vaccines, referred to as vaccine negativity. In doing so, this study elucidated how situational and cross-situational factors influence vaccine negativity. Specifically, this study tested how knowledge deficiency, or acceptance of scientifically inaccurate data about vaccines, and institutional trust influenced negative attitudes toward vaccines. Using the situational theory of problem solving as the theoretical framework, this study also identified and tested a knowledge-attitude-motivation-behavior framework of vaccine negative individuals' cognitions and behaviors about the issue.