Background The private health sector is a primary source of curative care for childhood illnesses in many low- and middle-income countries. Therefore ensuring appropriate private sector care is an important step towards improving outcomes from illnesses like pneumonia, which is the leading infectious cause of childhood mortality worldwide. This study aimed to provide evidence on private sector care for childhood pneumonia in Uttar Pradesh, India, by simultaneously exploring providers’ knowledge and practices and caregivers’ experiences. Methods We conducted in-depth interviews with a purposive sample of 36 practitioners and 34 caregivers in two districts. Practitioners included allopathic doctors, AYUSH providers, and drug sellers. Caregivers were mothers of children under the age of five with symptoms consistent with pneumonia who had seen one of those practitioners. Interview transcripts were analyzed thematically. Results Caregivers were generally prompt in seeking care outside the home, but many initially favored local informal providers based on access and cost. Drug sellers were not commonly consulted for treatment. Formal providers had imperfect, but reasonable, knowledge of pneumonia and followed appropriate steps for diagnosis, though some gaps were noticed that were primarily related to lack of (or failure to use) diagnostic tools. Most practitioners prescribed antibiotics and supportive symptomatic treatment. Relational and structural factors encouraged overuse of antibiotics and treatment interruption. Caregivers often had a limited understanding of treatment but wanted rapid symptomatic improvements, frequently leading to sequentially consulting multiple providers and interrupting treatment when symptoms improved. Providers were confronted with these expectations and care-seeking patterns. Conclusions This study contributes in-depth evidence on private sector care for childhood pneumonia in UP. Achieving appropriate care requires an enriched perspective that simultaneously considers the critical role of provider-caregiver interactions and of the context in which they occur in shaping treatment outcomes. Electronic supplementary material The online version of this article (doi:10.1186/s12913-017-2100-z) contains supplementary material, which is available to authorized users.