Naturalistic developmental behavioral interventions (NDBIs) are considered one of the best practices for autistic children and their families. Most NDBIs include a component of providing training and/or coaching to caregivers to enhance skill acquisition and generalization. The procedures to implement these NDBIs are often clearly delineated in manuals, which include intervention and implementation fidelity criteria to measure the providers' and caregivers' adherence to these procedures. Despite the identified benefits of achieving fidelity, there is a potential tension between fidelity and flexibility, especially when culturally adapting and implementing manualized NDBIs to be applied in community settings. We present four main issues and possible solutions when planning and implementing NDBIs and other manualized evidence-based practices with marginalized populations.