This qualitative study examined teachers’ described and observed classroom instruction around the science and engineering practices in the Next Generation Science Standards (NGSS). Seven secondary science teachers were surveyed and interviewed about their understanding and use of the science and engineering practices in their classroom teaching and then were observed to document their actual use of these practices. This study sought to describe (1) the variety of goals that teachers pursue in their classroom instruction and (2) the variety of instructional strategies teachers use to pursue those goals. Findings suggest that there were varying degrees of alignment between the teachers’ described and observed classroom instruction and between their classroom instruction and the goals of the NGSS. For example, it was easier for many teachers to describe instruction around the science and engineering practices that aligned with the goals of the NGSS than it was to enact instruction that aligned with the NGSS. I suggest that the difficulty teachers experienced with enacting these practices emerged from teachers’ misunderstanding of and misalignment with the goals of the NGSS. In order to address the challenges teachers faced in incorporating the science and engineering practices into their classroom instruction, I recommend some key features of professional development that may support teachers in refining their understanding, goals, and classroom instruction around these practices.