HIV/AIDS, a disease with neither cure nor vaccine, is a devastating pandemic. About 40 million people are infected, 4.1 million are infected annually, and 800,000 die from AIDS-related deaths each year. In developing countries, it is transmitted mainly heterosexually. Infection can be reduced through abstinence, faithfulness, and use of condoms. People must be knowledgeable about the disease and perceive that they are at risk of infection. This study investigated construction of sexual risk for HIV and behavioural change among youth in Masaka and Kampala districts in Uganda. The research studied perceived risk of youth in sexual activities, or activities which lead to sex and behaviour which youth adopt to reduce the risk. The findings have ample implications and applications for policy-makers, practitioners, researchers and scholars engaged in theoretical endeavours.