Background Mass media is an important educational tool for increasing knowledge of HIV and fighting stigmatisation associated with it in the society. Objectives This study aimed at assessing the “comprehensive knowledge” on HIV/AIDS among the adolescent´s girls in India. The second objective was to understand how mass media influences knowledge and stigmatising attitude towards people living with HIV/AIDS. Methods Secondary data analysis was done for the data available from the third round of the National Family Health Survey of India (NFHS-3). “Comprehensive knowledge” was defined as an individual who knew a) using a condom and having just one uninfected partner limits the risk of getting AIDS b) a healthy looking person can have AIDS and rejected the two most common misconceptions about AIDS transmission (transmission by mosquito bites and by sharing food). Stigmatising attitude included questions like, “if a teacher has HIV/AIDS but not sick, should he/she be allowed to continue teaching in school”. Media sources included broadcast media (TV programs/radio), print media (newspapers/display hoardings) and interpersonal sources (family/friends/health workers/community leaders). All data was analysed using the Statistical Package for the Social Sciences software. Descriptive statistics was used to examine the study subject’s exposure to mass media, knowledge about HIV/AIDS, and its sources of knowledge. In the process of analysis, logistic regression model was used to observe how mass media influences knowledge and stigmatising attitude towards people living with HIV/AIDS after controlling for confounders. Results 64.3% had ever heard about HIV/AIDS. The most common source of information about HIV/AIDS were broadcast media (88.5%) followed by interpersonal communication (50.7%) and print media (33%). Exposure to sources of HIV information was significantly related to HIV knowledge (OR = 4.5 for broadcast group; OR = 2.9 for print media and OR = 1.2 for interpersonal group) and less stigmatising attitude towards PLWHA (OR = 1.8 for broadcast group; OR = 2.2 for print media and OR = 0.9 for interpersonal group). Conclusions Exposure to mass media can help increase HIV/AIDS knowledge of adolescent girls. Enhancing its penetration in public can be an important strategy in disseminating HIV knowledge and reducing HIV related discrimination in India.