In 2013, California became one of the first states to adopt the rigorous Next Generation Science Standards (NGSS). However, the current state of science instruction does not support the conceptual shifts of the NGSS, which call for consistent science instruction K-12, increased inquiry, subject integration, as well as science instruction that connects students to their communities and their world. Therefore, teachers are in need of instructional support for science teaching that can enable them to achieve these higher expectations. This dissertation explored whether implementing a Project-Based Learning (PBL)-centered science specialist changed classroom teachers' frequency of science instruction and use of instructional strategies that support NGSS science delivery. In addition, this study examined how providing a PBL science specialist supported teachers in their comfort with using these more rigorous instructional strategies. Five elementary teachers participated in an action research project conducted over the course of a school year. The frequency with which teachers used the following instructional strategies was analyzed: connecting science to real world phenomena, accessing community resources, integrating science into other subject areas, and using inquiry in science instruction. Quantitative and qualitative data revealed that a PBL science specialist does support classroom teachers in implementing teaching practices aligned to the conceptual shifts implicated by the NGSS; however, individual growth rates varied by instructional strategy. The results of this study provide a foundation for the legitimacy of utilizing a PBL-focused science specialist to support teachers in shifting their instructional practices in order to achieve the Next Generation Science Standards. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]