The use of technology in assessment continues to evolve the field of educational measurement. This article reports on development and use of new accessible, technology-enhanced assessments designed to measure the three-dimensional science abilities of middle school students. The assessments were piloted with over 70 teachers and 8,000 students throughout the United States over a 3-year period. The adoption and implementation of technology-enhanced assessments is potentially challenging for educators, and numerous factors can influence whether new tools are successful in classroom contexts. The authors describe the assessments alongside insights from project surveys into the conditions that supported or hindered teachers' successful implementation and use of the new assessments in classroom settings. Results indicate that teachers found the assessments useful for supporting the transition to instruction based on Next Generation Science Standards and preparing students for new state science tests. Successful uptake of the materials in the classroom was supported by professional learning that anticipated teachers' content, technology, and pedagogical needs. While the assessments were overall successful, areas for potential improvement are also described, including improved reporting formats that are more teacher and student friendly.