The trend toward decentralization in supply chains has amplified the importance of behavioral factors. This paper investigates a supply chain system involving multiple suppliers and retailers, specifically focusing on integrating retailers’potential regret behavior into the supply chain decision-making model. The differences between regret-driven behavioral decision-making and artificial intelligence-assisted automated decision-making are compared, and the impact of retailers’regret is analyzed on their profits, upstream supplier profits, and the overall profitability of the supply chain. The results show that regret prompts deviations in retailers’order quantities relative to those determined through automated inventory decisions, which leads to an increase in the wholesale price that provides suppliers with competitive pricing advantages. These effects significantly influence the profits of supply chain members and the overall system and may be amplified as the supply chain expands. Therefore, managers should recognize and anticipate the implications of retailers’regret behavior to develop more effective decision-making strategies.