The Framework and NGSS conceptualize science inquiry learning as engaging in scientific practices including the practice of scientific modeling. Many K-12 teachers have not experienced science learning in this way and need opportunities to meaningfully make sense of scientific modeling, reflect on how this practice builds on or contrasts with their current science pedagogies, and establish a repertoire of strategies and tools for supporting scientific modeling in the classroom. Insufficient metamodeling knowledge—knowledge about the nature and purpose of scientific models (Schwarz & White, 2005)—impedes the ability to engage in the scientific practice of modeling. The first purpose of this study was to identify inservice teachers’ metamodeling knowledge. Analysis revealed that inservice teachers viewed the nature and purpose of scientific models in one three distinct ways: a visual or physical representation, a sensemaking tool, or a pedagogical strategy. The second purpose was to examine whether PD designed using ambitious science instructional practices (Windschitl et al., 2012) would help inservice teachers situated in a particular local context develop metamodeling knowledge consistent with the new and more global vision of science education. Findings suggest that learner-based PD activities designed using the ambitious science teaching framework foster inservice teachers’ metamodeling knowledge.