Sustainability has become an important determinant of competitive advantage.Firms are expected to demonstrate environmental and socialoutcomes. Boards of directors and top management teams (TMTs) arethe ultimate decision-making units responsible for meeting the needsof stakeholders. This paper investigates female representation and genderdiversity on boards and TMTs and firm sustainability performance.The main issue addressed is whether female representation and genderdiversity on boards and TMTs impacts the firm’s ability to meet sustainabilityindex requirements. Group diversity and critical mass literatureprovide the theoretical background. Group diversity literaturesuggests that diversity in attributes such as gender results in greatervariety of ideas, perspectives, knowledge, creativity and innovationin turn competitive advantage. Research on critical mass argues thatwomen representation on boards needs to reach a critical mass level beforeit can a ect decision-making process and firm performance.Thisstudy hypothesizes that 1)as gender diversity on the board and TMTincreases so too does the firm’s sustainability performance and 2)thenumber of females on the upper echelons (board and TMT) has a positiverelationship with sustainability performance. To test the hypotheses,binary regression was conducted. The sample consists of top 100best performing companies in the Istanbul stock exchange. The resultsprovide support for the hypotheses
