The measurement of willingness to communicate (WTC) in a second language (L2) has been pervasive in quantitative research particularly in the context of structural equation modeling. An important prerequisite for this line of research is to establish the psychometric properties of the instrument used to measure L2 WTC. This study involves measuring WTC in the Chinese context where English is learned as a foreign language (EFL), and identifying the factor structure underlying the L2 WTC scale adopted from the literature. Questionnaire data were collected from 1,013 university undergraduate students. An exploratory factor analysis and confirmatory factor analysis were respectively performed on random split-half samples. The results indicate that the participants reporting WTC in classroom situations outnumbered those expressing WTC in out-of-class situations. A two-factor structure of WTC was identified to adequately represent the data: WTC inside and outside the classroom. This paper concludes with a discussion of the results, caveats and implications for measuring WTC in EFL contexts.