This study is the first to examine contributions of proficiency subskills to pragmatic development. We used the latent growth curve modeling to reveal the causal relationships between proficiency subskills and pragmatic competence in 109 American learners of Chinese across two data points over three months abroad in China. Proficiency was measured by a standardized Chinese proficiency test with separate scores for listening, speaking, reading, and writing. Pragmatic competence was measured by a computerized oral discourse completion task assessing speech acts. Findings showed that pragmatic competence accrued along with increased proficiency. Changes of proficiency explained 54.1% of the variance in changes of pragmatic competence. Listening and speaking contributed more to pragmatic development than reading and writing did, indicating that when pragmatic competence is measured by an online spoken task, speaking and listening have stronger impacts.