Emotions are a core feature of human experience, with questions about what an emotion is dating back centuries. Recent psychological theorizing has proposed the coherence postulate, which maintains that 1) during emotions multiple response systems, including experience, behavior, and physiology, will become synchronized, or cohere, and 2) higher levels of coherence should contribute to beneficial outcomes. Although the coherence postulate serves as a critical foundation for how researchers think about and study emotion, a surprisingly small number of studies have directly tested it. The current work addresses three critical questions that arise from the coherence postulate for two types of coherence (i.e., experience-behavior and experience-physiology). First, what is the best approach for measuring coherence? Second, how much do emotional responses cohere with one another, across response systems and contexts? Third, is coherence associated with greater well-being? To address these questions, 160 female participants completed two standardized laboratory tasks (i.e., a film clip with amusing and sad scenes and a stressful speech) and a survey six months later assessing their well-being. During each task, I obtained continuous measures of emotional experience, behavior, and physiology (inter-beat interval, skin conductance level, and heart rate variability). For the first question, I systematically examined the influence of different timing resolutions of the emotional responses and lag windows (1, 2, 5, 10, and 15 s) on coherence estimates. Results suggest that the second-by-second timing resolution with the 10-s lag window present the best approach. For the second question, across the sample, I observed positive and significant levels of experience-behavior coherence for both the film clip and the speech. However, I found less evidence for experience-physiology coherence; except for a positive and significant level of experience-skin conductance coherence in the film clip, I found no evidence for other types of experience-physiology coherence. Additionally, coherence was generally not consistent across types of coherence (i.e., experience-behavior coherence was not related to experience-physiology coherence) and across the two tasks. For the third question, I found that experience-behavior coherence in the film clip was linked with greater well-being. The current findings provide the most consistent evidence for the presence and importance of experience-behavior coherence, whereas the evidence for the presence and importance of experience-physiology coherence is much less clear.