Although language learners' knowledge of second language (L2) speech acts is postulated to be substantially influenced by learner variables, there is little empirical evidence of the influence of pragmatic motivation (PM) and willingness to communicate (WTC). To address this gap, this study sought to investigate the impact of PM and WTC as two important multifaceted learner variables on L2 speech-act knowledge. The participants included 500 Persian-speaking learners of English as a foreign language. The researchers developed and validated three instruments for data collection: a multiple-choice discourse completion task (MDCT) including five common English speech acts, a PM questionnaire, and a WTC questionnaire. Data were collected in two subsequent phases. First, the MDCT was administered, and then the participants filled out the two questionnaires. Data analysis using multiple regression revealed that both PM and WTC significantly predicted L2 speech-act knowledge. However, PM turned out to be a stronger predictor of this knowledge than WTC. The findings imply that PM and WTC are implicated in L2 pragmatic knowledge and hence language teachers should consider these two variables to help learners enhance their pragmatic acquisition.