Even though the e-commerce supply chain operations have paid continuous attention in improving their operational capabilities and optimizing costs, strategic interactions and management issues still exist, thereby impeding the optimal performances. Game theory-based contract models have vastly been adopted in supply chain studies to resolve issues of strategic interactions and decision-making among different supply chain members. In that context, contracts include incentive compatibility constraints to ensure that the players have sufficient incentive to remain within the contract. However, less attention has been given to contract models, which includes multi-levels of e-commerce-based supply chain operations. Therefore, this study develops a cost-sharing contract, including incentive compatibility constraints for the three-level e-commerce supply chain to address the issues of cost information asymmetry. We consider cost information asymmetry issues of the upstream and downstream of the supply chain where e-tailer shares a fraction of operational costs of the product supplier and the 3PL operator. The results of this study emphasize that the cost-sharing contract significantly reduces the overall supply chain cost while proving Pareto-improved outcomes in terms of cost minimization.