CONTEXT: Supporting patients' spiritual needs is central to palliative care. Adolescents and Young Adults (AYAs) may be developing their spiritual identities; it is unclear how to navigate conversations concerning their spiritual needs. OBJECTIVES: To (1) describe spiritual narratives among AYAs based on their self-identification as religious, spiritual, both, or neither; and, (2) identify language to support AYA spiritual needs in keeping with their self-identities. METHODS: In this mixed-methods, prospective, longitudinal cohort study, AYAs (14-25 years-old) with newly diagnosed cancer self-reported their "religiousness" and "spirituality." One-on-one, semi-structured interviews were conducted at 3 time-points (within 60 days of diagnosis, 6-12, and 12-18 months later), and included queries about spirituality, God/prayer, meaning from illness, and evolving self-identity. Post-hoc directed content analysis informed a framework for approaching religious/spiritual discussions. RESULTS: Seventeen AYAs (mean age 17.1 years, SD=2.7, 47% male) participated in 44 interviews. Of n=16 with concurrent survey-responses, 5 (31%) self-identified as both "religious and spiritual," 5 (31%) as "spiritual, not religious," 1 (6%) as "religious, not spiritual," and 5 (31%) as neither. Those who endorsed religiousness tended to cite faith as a source of strength, whereas many who declined this self-identity explicitly questioned their pre-existing beliefs. Regardless of self-identified "religiousness" or "spirituality," most participants endorsed quests for meaning, purpose, and/or legacy, and all included constructs of hope in their narratives. CONCLUSIONS: AYA self-identities evolve during the illness experience. When words like "religion" and "spirituality" do not fit, explicitly exploring hopes, worries, meaning, and changing life perspectives may be a promising alternative.