Objective <p>The diagnosis of adolescent polycystic ovarian syndrome is based on the presence of menstrual irregularity and clinical/biochemical hyperandrogenism. However, the cut-off for normal adolescent androgen levels remains unclear. Normative data for androgens by LCMS for Indian adolescents is not available. We measured serum androgens by LCMS and DHEAS by immunoassay and their relation to the menstrual cycle phase and body mass index in healthy adolescent girls.</p> Methods <p>This was a cross-sectional study in North India among girls studying in public schools. A total of 1469 girls aged 10–18 years were screened out of which 977 consented for blood sampling.</p> Results <p>A total of 628 post-menarcheal with normal menstrual cycles and 142 premenarcheal girls were included. Normative data for serum testosterone, androstenedione, DHEA, DHEAS and DHT are presented as per post-menstrual (PMA) and chronological age. There was a progressive increase in levels of androgens with PMA with testosterone and androstenedione being significantly higher in the mid-cycle and luteal compared to the follicular phase. The upper reference limit (97.5th percentile [95% CI]) for testosterone in girls with post-menstrual age &gt; 1 year in the follicular (<i>n</i> = 104), mid-cycle (<i>n</i> = 191) and luteal phase (<i>n</i> = 210) was 1.564 [1.431–1.698] nmol/l, 2.094 [1.90–2.77] nmol/l and 2.08 [1.837–2.166] nmol/l. Androstenedione and DHEAS levels were significantly higher in obese compared to normal weight girls whereas DHT levels were lower.</p> Conclusions <p>This study provides normative ethnicity-specific data for androgens using LCMS in Indian girls with normal menstrual cycles according to the post-menstrual age which can help define hyperandrogenaemia in adolescent girls and aid in the diagnosis of adolescent PCOS and ovarian/adrenal dysfunction irrespective of menstrual phase.</p>