Today, the workforce is becoming increasingly diverse. This is caused by some major trends. Amongst them are: globalization, increasing labor force participation of women, and significant demographic changes. Due to the associated challenges, companies are searching for answers on how to react to this development. However, research findings are inconsistent and fragmented. Organizational climate research, which is particularly important for today's work environments that are centered around workgroups, offers important insights to diversity research. Therefore, this dissertation links the fields of diversity and organizational climate in its focus on diversity climate or climate for inclusion. By doing so, it offers important insights in how to manage organizations more effectively.Study 1 identifies a significant gap in the amount of high quality empirical research that has been conducted on disability versus other diversity dimensions such as age, gender and culture. Through expert interviews it identifies methodological challenges in the field of disability research as a cause of this gap and offers possible solutions to these obstacles. Ultimately, it urges scholars to recognize that disability is an important yet often neglected dimension of diversity and calls for more research on the topic.The second study investigates the top-management leadership-performance relationship in a sample of 20,639 employees from 157 companies. Transformational leadership climate as one form of organizational climate and organizational identity strength are identified as mediators through which top managers' leadership can influence their firm's performance. It is the first study to show the connection between identity strength and performance at the organizational level. Furthermore, it is one of the rare studies that examine cascading effects of leadership.Study 3 combines the fields of diversity and organizational climate by assessing the effects of diversity climate on performance at the group level of analysis. In a sample of 7,689 employees from 211 work groups, work group discrimination is identified as a mediator of the relationship. In addition, it is shown that this relationship is pronounced in larger work groups. Although discrimination is often cited as an important mediating mechanism between group climate and performance, empirical tests of these relationships have been lacking until now.