Originating from Vygotsky’s Sociocultural Theory, dynamic assessment (DA) proposes a novel approach to second language acquisition (SLA) research according to which a dialectical relationship is envisaged between instruction and assessment. Although DA has been applied to some areas of SLA, there are areas, such as interlanguage pragmatics (ILP), that have been neglected. To address the issue, 40 university students of two proficiency levels were selected and assigned randomly to 1 of 4 groups consisting of two DA and two Non-DA groups. Each group received instruction concerning how to use appropriate request and apology strategies in the English language. However, following Lantolf and Poehner (2011), DA groups received ZPD-sensitive feedback whereas NDA groups received no more feedback but were assessed according to their independent performance. All participants completed a pretest, a posttest, and a delayed posttest of request and apology speech acts that were rated by two native speakers of English on a 6-point Likert scale. The findings revealed that DA groups outperformed NDA groups and that DA groups of both high and low proficiency levels differed significantly from pretest to posttest to delayed posttest. However, high NDA group didn’t show such a difference. The results also showed no interaction between proficiency and instruction indicating that instruction, but not proficiency, had a significant effect on posttest and delayed posttest performance of the students. The findings may be revealing in that they support DA and its applicability to ILP instruction.