Demand forecasting is a field of analysis used to understand and predict sales potential. It is the fundamental element affecting all other activities of supply chain management. Accurate forecasting determines production planning, resource allocation, and forward or backward integration. Various forecasting models predict future market requirements to enable business plans. A well-predicted sales volume enables the effective management of strategic decisions such as production, inventory, purchasing, investment, and employment. Businesses frequently use qualitative methods, incorporating human judgment, in addition to quantitative methods to forecast demand. Periods of crisis and uncertainty, the lack of data, or the need to refine quantitative analyses make judgmental decisions valuable. This study discusses the role and importance of human judgment in demand forecasting and presents a detailed literature review for both the literature and businesses.