OBJECTIVES: Patients with tuberculosis (TB) generally are instructed to isolate at the beginning of treatment in order to prevent disease transmission. The duration of isolation varies and may be prolonged (ie, lasting 1 month or more). Few studies have examined the impact of isolation during TB treatment on adolescents, who may be more vulnerable to its negative effects. METHODS: This study took place from 2018 through 2019 in Lima, Peru, where the Ministry of Health mandates the exclusion of patients with TB from educational institutions for at least 2 months. Using semi-structured guides, we conducted individual in-depth interviews with adolescents who received treatment for drug-susceptible TB, their primary caregivers and health providers. We performed thematic analysis of the transcribed interviews. RESULTS: We interviewed 85 participants: 34 adolescents, 36 caregivers and 15 healthcare workers. At the time of their TB diagnoses, 28 adolescents were in secondary, postsecondary, vocational or military school. Adolescents with drug-susceptible TB were prescribed home isolation usually for 2 (and occasionally for 1) months. Consequently, they could neither attend school nor socialise with family members or friends. Two primary themes emerged from the interviews. First, as a result of their exclusion from school, most adolescents fell behind academically and had to repeat a semester or academic year. Second, absence from school, separation from friends and loved ones, and reinforcement of TB-related stigma (arising from fear of TB transmission) harmed adolescents' mental health. CONCLUSION: Prolonged isolation led to educational setbacks and emotional trauma among adolescents with TB. Prolonged isolation is not supported by current evidence on TB transmission and is problematic from a human rights perspective, as it violates adolescents' rights to education and freedom of movement. Isolation recommendations should be re-evaluated to align with data on TB transmission and the principles of patient-centred care.