In today’s rapidly changing global world, the sustainability of an organization depends not only upon its financial performance, but also upon its environmental and social performance. It is suggested that policy makers, and corporate and engineering managers integrate economic, environmental and social objectives i.e., the triple bottom line (TBL) into their overall strategic plan and consider these objectives in their decision making. Investment planning and capital budgeting decisions play a critical role in aligning an organization with its economic, environmental and social strategic objectives. This research introduces a new decision making tool that integrates both financial and non-financial performance measures into the process of investment planning and capital budgeting via the TBL. It makes use of stakeholder theory for group decision making, analytic network process (ANP) as a decision support tool and stochastic linear programming to create an optimal investment portfolio. This new tool evaluates and prioritizes a set of projects and creates a long-term balanced investment portfolio based upon the perspectives and priorities of the stakeholder groups and decision makers. It can assist decision makers with developing and making proactive decisions which support the strategy of their organization with respect to economic, environmental and social issues, ensuring the sustainability of their organization in the future. To create a sustainability culture both in academia and business environment, and to encourage communities for sustainable development, a real life application of the developed tool is provided through coordination with Sustainable Pittsburgh and Cranberry Township business leaders.