Some writers (Black and Wiliam in "Phi Delta Kappan" 80(2):139-148, 1998; Clark 2012; Panadero and Jonsson in "Educational Research Review" 9:129-144, 2013) have hypothesized a link between formative assessments (FA) and self-regulated learning (SRL). FA give students an opportunity to play an active role in their learning exercise, in other words to exercise SRL, while SRL gives the learners the will and skill to take advantage of the feedback offered by FA to progress. This paper provides empirical evidence of this link through interviews of 13 students (aged 16-17) from an all-girls school who were assigned two tasks which tested the same cognitive skills but set in contrasting contexts: one was a paper-and-pen class assignment while the other, in a live online forum. Data were gathered through one-to-one interviews which probed students' use of SRL in the 3 phases (Forethought, Performance, and Self-reflection) based on Zimmerman's cyclical model of self-regulation (2000). The findings helped shed light on how different FA contexts can affect students' use of SRL, specifically in terms of their motivation, metacognition, and behavior.