Even with significant resources and professional development committed to science, technology, engineering, and mathematics (STEM) education, some elementary teachers do not feel prepared to integrate multidisciplinary content or implement project-based learning (PBL). Further research is needed for school leaders to shift traditional education practices to provide effective STEM-PBL in elementary schools. Distributed leadership and constructivist learning theories were the study's foundation for understanding school leadership in complex school systems and the underlying pedagogy needed for quality STEM instructional practices. The purpose of the basic qualitative design was to explore the distributed leadership practices of STEM educators in elementary schools implementing STEM-PBL. From a population of 225 educators in Florida, 15 participants were selected for the sample who met the criteria of having at least 3 years of experience in a STEM role, were utilizing PBL, and were working with elementary students. A questionnaire was used for recruitment and to verify participants met the study's criteria. Data was collected through virtual semi-structured interviews and analyzed using Braun and Clark's thematic analysis. Themes emerged to reveal formal and informal leadership actions to support traditional classroom teachers implementing constructivist project-based learning instructional practices. Recommendations include further research on how elementary school leaders are creating the culture needed for distributed leadership practices and setting the expectations for STEM-PBL. [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.]