OBJECTIVE: As part of a larger implementation trial for cognitive processing therapy (CPT) for posttraumatic stress disorder (PTSD) in a community health center, we used formative evaluation to assess relations between iterative cultural adaption (for Spanish-speaking clients) and implementation outcomes (appropriateness and acceptability) for CPT. METHOD: Qualitative data for the current study were gathered through multiple sources (providers: N = 6; clients: N = 22), including CPT therapy sessions, provider fieldnotes, weekly consultation team meetings, and researcher fieldnotes. Findings from conventional and directed content analysis of the data informed refinements to the CPT manual. RESULTS: Data-driven refinements included adaptations related to cultural context (i.e., language, regional variation in wording), urban context (e.g., crime/violence), and literacy level. Qualitative findings suggest improved appropriateness and acceptability of CPT for Spanish-speaking clients. CONCLUSION: Our study reinforces the need for dual application of cultural adaptation and implementation science to address the PTSD treatment needs of Spanish-speaking clients.