Urbanization leads to loss of vegetation and converting pervious areas into built-up and impervious areas, and consequently, urban areas expose higher temperatures as compared to surrounding rural areas, which is called Urban Heat Island (UHI). The UHI affects the urban environment and causes heat-related diseases and mortality that have increased over the last centuries. Considering the severity of the UHI problem, enormous research has been conducted and an extensive range of literature is available on this topic. This paper reviews the causes, modelling and mitigation strategies of the UHI. The urban infrastructure and anthropogenic heat sources are the main driving factors in developing the UHI in cities. Many approaches including observation and modelling techniques are used to understand the formation, causes and mitigation of the UHI. The formation and causes of the UHI largely depend on the size, shape and urban infrastructure of the cities as well as climatic conditions. Although various modelling techniques are used to study UHI, there are still lacks in all models to precisely represent the physical phenomena and complex urban infrastructure. Many UHI mitigation strategies are examined by numerous studies, while the increased urban vegetation is a more environmentally friendly solution. The study summarizes the important features and limitations of different modelling techniques and mitigation measures of the UHI. This study also identifies research gaps and proposes areas for further research.