A multiple agent-based system is intended to capture complex behavioral patterns by utilizing a collection of autonomous computer systems (called agents) that can interact with decision makers and then learn, perform, and delegate tasks on their behalf. With its ability to handle a large amount of information from heterogeneous sources in dynamically changing environments, a multiple agent-based system can significantly improve the company's business intelligence and operational efficiency. Though rarely used in demand planning, this paper proposes a multiple agent-based system for demand forecasting of ice cream which poses unique challenges due to volatility and seasonality of ice cream consumption. To validate the usefulness of the proposed system for demand planning, the forecasting outcomes of the proposed system was compared to those of traditional forecasting techniques. Our experiments showed that the proposed multiple agent-based system outperformed its traditional forecasting counterparts in terms of its accuracy and consistency.