Urban heating is one of the most critical urban issues. As a result, the thermal environment in cities is getting hotter every day, intensifying the risk of heat stress. An urban built environment combines diverse microclimatic conditions, including varieties of urban morphological settings that distinctly affect the outdoor thermal environment. It can vary thermal loads and consequently affect the thermal comfort of inhabitants. The thermal comfort in urban open spaces influences urban dwellers’ living quality, health, and well-being. Urban open areas are essential for social, cultural, and economic values. Outdoor thermal comfort (OTC) is a complex urban scenario that includes the role of various parameters and defines the perceived quality of urban open spaces. The amalgamation of natural and built environments is critical in controlling OTC. This study investigates the parameters responsible for thermal discomfort in urban open spaces. The study will thoroughly review the existing literature and focus on various factors governing heat exchange between urban built environments, giving rise to dissimilar thermal environments in open spaces. The microclimatic, physical, and personal parameters are recognized, classified, and decomposed. The interrelationship between the parameters is explored and analyzed. This work will cooperate with the scientific community to scrutinize thermal comfort in urban open spaces. The study's outcome will provide insights and scope for future studies examining the quantitative influence of various parameters identified for making resilient future cities.