Aims: The combination of knowledge, attitudes and practices is an important psycho-behavioural mechanism in the disease-management strategies of HIV patients. This study reviews the global evidence of knowledge, attitudes and practices (KAP) of HIV patients. Design: Systematic review. Data sources: Four databases- Pubmed, Scopus, Science Direct and Web of Science (WOS) were searched from January 10 to April 25, 2021. Methods: Databases were searched for the predefined keywords of “knowledge”, “attitudes”, “practices”, “people living with HIV/AIDS” and “HIV/AIDS”. The inclusion criteria were limited to time range, language and study types and nature. PRISMA was followed and JBI quality assessment tools for cross-sectional and qualitative studies were used. Results: A total of 18 papers have been selected for the extraction of 1964 articles. The KAP were assessed related to nutrition, infant feeding, disclosure of HIV/AIDS, WASH (or hygiene), oral health, cancer-related domains with HIV/AIDS and HA(ART). Relevant dimensional KAP were incorporated with the basic items about HIV/AIDS. Overall, a mixed level of knowledge, discriminatory attitudes and malpractices were observed throughout the study. Socio-economic, counselling, support and dimensions related factors were identified as associated risk factors. Conclusion: Variation in assessing KAP is a critical problem and unique, outcome-based KAP assessment tools integrated with qualitative assessments were suggested to examine the interrelationship of the KAP components and outcomes.