Grounded in the process component model of emotion and a mixed-methods approach, this study developed the English Speaking Enjoyment Scale to fill the methodological gap in measuring enjoyment in foreign language speaking. The participants were three groups of Chinese university students of English. The first group of students (n = 53) participated in an open-ended survey aiming to elicit affective, cognitive, motivational, expressive, physiological, and other responses to enjoyment in English speaking. Thematic analysis of the collected qualitative data yielded 26 themes. The preliminary English Speaking Enjoyment Scale was created based on the first 13 themes and was examined in exploratory factor analysis (n = 466) and then confirmatory factor analysis (n = 535). A 12-item instrument was achieved, which constituted two subscales—the English Speaking Enjoyment Indications-Stable Subscale (nine items) and the English Speaking Enjoyment Indications-Dynamic Subscale (three items). Both the scale and subscales indicated good psychometric properties. Based on this, we argued that the English Speaking Enjoyment Scale is a sound scale to measure the target construct. The scale's similarities and differences in contrast to existing measures of domain-specific foreign language enjoyment are also discussed. Implications of the findings are put forward.