Purpose: The purpose of this phenomenological study was to explore the lived experiences of secondary traumatic stress (STS) among elementary teachers from Title I schools. This study sought to understand teachers' perceptions of STS and the personal, behavioral, and environmental factors that influence their impact. Methodology: This study utilized a phenomenological research design. The researcher employed a purposeful sampling strategy to select elementary teachers from Title I schools who experienced symptoms of the phenomenon STS. Data were collected during one-on-one, semistructured interviews with 15 elementary teachers from 11 Title I schools in Southern California. Findings: Analysis of the data revealed six overall themes related to teacher STS: (a) perceptions of students' home environments, (b) challenges supporting students' needs, (c) emotional awareness, (d) desired structures and protocols, (e) coping and support, and (f) fulfillment. Conclusions: This study's findings revealed that teacher STS reactions stem from more than exposure to student trauma. Knowledge of compounding stressors from students' home environments and the emotional burden teachers' experience while supporting competing challenges in the classroom exacerbates symptoms. Bandura's (1989) concept of triadic reciprocal determinism provides a novel perspective regarding the interplay of personal, behavioral, and environmental factors that create pathways for STS to manifest as well as the conditions that lead to fulfillment and growth. Recommendations: Teachers should work to understand the factors that place them at risk for STS. Districts should work to normalize STS, placing teacher STS alongside student trauma in the development of trauma-informed care systems and practices. Organizations should take an active role developing formalized structures for employee self-care that favor a trauma-informed approach, including effective supervision, collaboration, trauma-specific training, and work-life balance. Training should include examining the bidirectional influences of personal, behavioral, and environmental factors that induce and mitigate symptoms. Recommendations include conducting studies of larger sample sizes and other populations utilizing the same theoretical framework to confirm or extend findings. Additionally, future research should examine the impact of teacher-adverse childhood experiences on STS. Also, examining posttraumatic and vicarious growth could serve to inform intervention programs, coping strategies, and support structures. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]