Modeling & Simulation (M&S) studies have been widely used in industry to gain insights into existing or proposed systems of interest. The majority of these studies focus on productivity-related measures to evaluate system' performance. However, this predominant focus on productivity may need to change since sustainability has become an increasingly important consideration in managerial discourse on organizational development. In this paper, the authors review and argue for a hybrid/mixed method approach towards modeling for sustainability; they present a review of literature with the aim of providing a synthesized view of M&S approaches which have previously been used to model sustainability; this study also explores the specific characteristics of sustainability in order to investigate the challenges in developing models for sustainability and to analyze what seems to be a holy grail for modelers.