The paper reports results of three studies that used a formative assessment (FA) framework to compare schools that vary in their level of functioning as professional learning communities with respect to three processes: classroom assessment (study 1), development and implementation of school-based curriculum (study 2), and pedagogical conversations at teachers' lounge professional meetings (study 3). When performed at their best, these three are inquiry processes that follow the phases of formative assessment cycles. Results supported the conclusion that school-based professional learning communities (SBPLC) make a difference in terms of FA practices enacted at both classroom and organizational levels. Moreover, classroom culture seems to mirror the organizational culture, where attributes considered as enhancing FA practice are clearly more noticeable in the high SBPLC group than in the low one. (Contains 1 figure and 7 tables.)