The purpose of this study is to propose and test a tree-like structure for assessing the operational performance of an eco-industrial park composed of a managerial, focal company, and five manufacturing companies that exchange, generate, or reuse energy, waste, and by-products from different sources. The top term is the EIP operational overall performance, supported by indicators retrieved from the literature and organized in four constructs: (i) internal relationships; (ii) external relations; (iii) energy recovery; and (iv) materials recovery. The first construct encompasses relationships between companies, leadership, mutual trust and technological exchange, communication, and integrated information systems. The second encompasses relations with government, stakeholder communication, compliance, and social responsibility. The third encompasses the reuse of biomass, refuse-derived fuels, heat, fluids (water, gases, steam), and the energy efficiency of facilities. The last encompasses reuse of waste, reuse of byproducts, efficiency in the logistical process, and efficiency in the manufacturing process. The structure embraces the three main pillars of sustainability, since the first and second constructs include social issues, whereas the third and fourth include economic and environmental ones. The research method is qualitative modeling. Managers employed a Likert scale of agreement [0 = strongly disagree ... 1 = strongly agree] to evaluate the importance and performance of indicators. The importance depends on the influence on the construct and the influence that the construct exerts on the top term. The performance depends on the contribution of the indicator to the overall operational result of the EIP. Results show that there is no need to reallocate or replace strategic resources among the constructs, but also show that the overall performance is only 59 % of the maximum possible. Two constructs, internal relationships, and energy recovery require control actions and further managerial improvement.