Background: Title X-funded family planning clinics have been identified as optimal sites for delivery of pre-exposure prophylaxis (PrEP) for HIV prevention. However, PrEP has not been widely integrated into family planning services, especially in the Southern U.S., and data suggest there may be significant implementation challenges in this setting. Because Title X clinics vary greatly in provider-, organizational-, and systems-level characteristics, there is likely variation in capacity to implement PrEP across clinics. Methods: We conducted a survey from February-June 2018 among providers and administrators of non-PrEP providing Title X-funded clinics across 18 southern states. Survey items were designed using the Consolidated Framework for Implementation Research (CFIR) to assess constructs relevant to PrEP implementation. To explore the heterogeneity of CFIR-related determinants and identify distinct sub-groups of Title X clinics, a latent profile analysis was conducted using nine CFIR constructs: complexity, relative advantage, cost, attitudes, implementation climate, compatibility, leadership engagement, available resources, and cosmopolitanism. We then conducted a multi-level analysis (accounting for nesting of participants within clinics) to test whether group membership was associated with readiness for implementation of PrEP, controlling for key sociodemographic characteristics. Results: 414 healthcare providers/administrators from 227 non-PrEP providing Title X clinics participated in the study. We identified six sub-groups of clinics that each had distinct patterns of perceptions across the CFIR-related determinants. Clinic sub-groups included: “High Capacity”, “Optimistic”, “Advantageous”, “Moderate”, “Incompatible”, and “Resource Constrained”. Group membership was related to numerous provider-level (i.e., ability to prescribe medication), clinic-level (i.e., provision of primary care), and community-level characteristics (i.e., county-level HIV prevalence). In comparison to the “Moderate” group (which held neutral perceptions across the CFIR constructs), the “High Capacity” and “Optimistic” groups had significantly higher levels of implementation readiness; and the “Resource Constrained group had a significantly lower level of implementation readiness.Conclusions: Latent profile analyses can help researchers understand how context-specific implementation determinants vary across individuals and settings (such as clinics), allowing implementation planning to be tailored to the specific needs of each segment of the population.