We investigated changes in district science coordinators' understandings and practices following their participation in a statewide professional development (PD). Participants included 13 male and 34 female science coordinators from 42 different school districts in Virginia. Data included presurvey, postsurvey, and delayed postsurvey responses; follow-up interviews; and observations of the PD and of science coordinators at work in their district. Results indicated that science coordinator understandings about pedagogy and job responsibilities changed following the PD and were aligned with the goals of PD. However, coordinators' practices following PD did not fully reflect their understandings about pedagogy. Results suggest that PD aligned with a situated learning framework, specifically the components of collaboration and authentic context, supports coordinators in changing their understandings and some of their practices.