The heightened sophistication of phishing attacks results in billions of dollars of financial losses, loss of intellectual property, and reputational damage to organisations. Past work examining determinants of phishing susceptibility has been dominated by cognitive theoretical perspectives. However, recent research has also revealed the importance of emotion in phishing susceptibility. This study expands our understanding of phishing susceptibility by adopting an affective lens. Using an integrative perspective of emotion, we build on the Affective Infusion Model (AIM) to predict the effects of valence, certainty, and arousal on phishing susceptibility. We pilot our manipulations (N = 241) and then test our hypotheses using a mock phishing experiment (N = 474) in which phishing messages are sent directly to participant inboxes. We demonstrate that messages inducing positive valence and low certainty result in higher phishing susceptibility. This study contributes to phishing literature by illuminating the critical role that emotion plays in altering recipients’ susceptibility in the processing of phishing messages and has implications for scholars, practitioners, and organisations.