The diversity of internal and external customers continues to increase with social, economic and global changes. This presents an array of opportunities and challenges for organisations. In the present paper we argue that whether interactions between diverse individuals results in benefits or deficits for the organisation depends largely on the level of openness to dissimilarity present in the exchange. This proposition is developed and presented in a model linking types of diversity to organisational group process and outcome effects. Implications for interactions with diverse internal and external customers are suggested. Structural and management characteristics expected to enhance dissimilarity openness in the workforce are offered.