This research investigates the variables influencing willingness to communicate (WTC) in English as a foreign language (EFL) context in Taiwan. A hypothesized EFL WTC model with six layers focusing on factors related to individual differences was proposed and the EFL WTC model was reinterpreted as a serial mediation model. Ten latent variables, including openness to experience, conscientiousness, agreeableness, extraversion, neuroticism, international posture, motivation, self-perceived communication confidence, EFL WTC, and frequency of using English in the classroom, were used to construct the model. Stratified random sampling was adopted and a questionnaire was administered to 701 university students in Taiwan. The results of structural equation modeling indicated that the EFL WTC model was an adequate fit to the Taiwanese context and validated the reinterpretation of the model as a serial mediation model. The findings supported the interrelationships among different variables and provided a different perspective on WTC in an EFL context.