In the absence of a cure and/or vaccine, the best approach to HIV is to focus on prevention. However, preventative measures that are presently available in Nigeria do not target persons with intellectual disability despite their vulnerability to HIV infection. This study sought to compare the HIV knowledge, attitudes, and sexual practices of mildly/moderately intellectually impaired learners (IIL) and mainstream learners (ML) in Nigeria; to explore the contextual factors informing these, as well as both groups‗ exposure to HIV education. It also tested the relevance of the I-Change Model in predicting sexual abstinence among learners with intellectual disability. Findings can assist in developing tailored HIV prevention education for Nigerian learners with intellectual impairment. This cross-sectional, comparative study utilised mixed methods to investigate HIV knowledge, attitudes, and sexual practices among mildly/moderately IIL and ML in Nigeria. Mildly/moderately IIL (300) and ML (300) within the age range of 12-19 years in special and regular schools completed a questionnaire based on the I-Change Model. Focus group discussions and in-depth interviews were used with learners to explore contextual factors informing their HIV knowledge, risk perception, sexual behaviours and access to HIV education and services. Key informant interviews were used as independent sources of the same information with their teachers. Learners with intellectual impairment were less aware of HIV/AIDS than their non-disabled peers (p < 0.001), had lower HIV knowledge scores (p < 0.001) and lower HIV risk perception scores (p < 0.001). Sexual experience was reported by 79 (26.3%) of the IIL sample compared to 48 (16.0%) of the ML sample (p = 0.002). Girls with intellectual disability were 3.71 times more likely to report a history of sexual abuse than non-disabled girls (p = 0.041). Inconsistent condom use with casual partners (p < 0.001) and non-use of condoms during the last sexual activity (p < 0.001) was higher in IIL. The I-Change Model was most effective in predicting sexual abstinence among IIL, particularly regarding factors related to motivation and intention. Intellectually impaired learners were more vulnerable to HIV infection due to neglect, poverty, sexual abuse/exploitation, stigmatisation, pressure from non-disabled peers, denial of HIV education, and inaccessible HIV-related services. Teachers only provided them with sexuality and HIV education when sexual activity was suspected and/or from age 18. The content of such education comprised mainly warnings, misinformation and corporal punishment to instil fear and desexualise them. Thus, this group of learners was limited in the way they experienced and expressed their sexuality. Unlike with their non-disabled peers, teachers attributed sexual activity among IIL solely to natural urges without emotional involvement. Contrary to teachers‘ opinions, some IIL were involved in symbiotic, loving relationships with their II peers. In addition, those that were not yet in such relationships expressed the desire to find non-discriminatory partners in the future. They explored their sexuality through intimate relationships, sexual intercourse, peeping at the opposite sex, pornography, and masturbation. Condoms were less available to IIL than ML, and they lacked the self-efficacy to use them. They were also less available to II girls than II boys. Female learners with intellectual impairment often had older sexual partners due to sexual abuse/exploitation, unlike their non-disabled peers, who embarked on such relationships for financial/material gains. The findings of this study indicated that IIL were sexual beings, just like their non-disabled peers, and at higher risk of HIV infection than the latter. Stigma and discrimination are the root causes of all the disadvantages/barriers that IIL experience in accessing HIV information, education and related services. Therefore, there is the need to put stigma reduction strategies in HIV response to safeguard the health of IIL. In addition, there is a need for the development of a gender-sensitive, tailored sexuality and HIV/AIDS educational format for learners with intellectual disability in Nigeria. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.