SETTING: In 2012, Peru's National Tuberculosis Program (NTP) reported that children aged 0-14 years accounted for 7.9% of the country's tuberculosis (TB) incidence. This figure is likely an underestimate due to suboptimal diagnosis of childhood TB. OBJECTIVE: To identify barriers to childhood TB diagnosis in Lima, Peru. DESIGN: Using semi-structured guides, moderators conducted in-depth interviews with four NTP administrators and five pulmonologists specializing in TB and 10 focus groups with 53 primary care providers, community health workers (CHWs), and parents and/or guardians of pediatric TB patients. Two authors independently performed inductive thematic analysis and identified emerging themes. RESULTS: Participants identified five barriers to childhood TB diagnosis: ignorance and stigma among the community, insufficient contact investigation, limited access to diagnostic tests, inadequately trained health center staff, and provider shortages. CONCLUSION: Recent efforts to increase childhood TB detection have centered on the development of new technologies. However, our findings demonstrate that many diagnostic barriers are rooted in socio-economic and health system problems. Potential solutions include implementing multimedia campaigns and community education to reduce ignorance and stigma, prioritizing contact investigation for high-risk households, and training primary care providers and CHWs to recognize and evaluate childhood TB.