Few studies have investigated the impact of English language programs on L2 students studying in Canadian universities. This article reports on questionnaire responses of 641 L2 students studying in 36 different English language programs in 26 Canadian universities. Programs were identified by their activity emphasis as either English as a Second Language (ESL) or English for Academic Purposes (EAP). Activity emphasizing speaking, social interaction, and general language development (e.g., in vocabulary, structure, idioms) was viewed as ESL; whereas, activity that emphasized academic reading, writing, and language development (e. g. preparing lab reports, writing research essays, note-taking from lectures) was considered EAP. Structural equation modeling (SEM) procedures were used to examine the network of relationships between language program emphasis and participants’ background characteristics in influencing academic and social engagement. A model of moderated mediation was confirmed. In other words, language program activities were found to account for variation in strategies which mediated academic and social engagement, however, the impact was moderated (lessened or strengthened) by three personal background factors: anxiety, stress, and motivation. This study refines our understanding of the positive impact of ESL and EAP programs on L2 university students’ academic and social engagement.