High school chemistry is essential. Every citizen needs basic chemistry background to understand current events, and millions more can benefit from further study. Nevertheless, students do not always continue learning chemistry, even when they could do so. The loss of potential learning is significantly more common for girls, economically disadvantaged students, and underrepresented minority (URM) students. This action research study investigated how to keep capable students at one high school on the chemistry pipeline, defined as taking pre-AP Chemistry, taking AP Chemistry, taking and passing the AP Chemistry Exam, and possibly pursuing further chemistry education or activities. Contributing factors that help or hinder pipeline persistence were investigated, and an action research intervention was done to improve chemistry and metacognitive skills. Students are more likely to persist in the chemistry pipeline when they have adequate algebra skills, when they see themselves as having qualities of scientists, when they have connected adults who encourage them, and when they feel they can get sufficient extra help and time to spend on their chemistry studies. These results and the literature inform recommendations for additional algebra preparation as well as purposeful chemistry communities of practice with content and skill supports, led by appropriate role models. [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.]