Diversity, equity, and inclusion (DEI) are complementary terms and concepts that refer to strategies and processes that enable organizations to become more reflective of and responsive to the identities, values, and experiences of important stakeholder groups. In doing so, these organizations may better achieve their own missions and improve the well-being of these stakeholder groups and of society at large. In the United States, DEI has its roots in social policies designed primarily to remedy the effects of historical barriers to opportunity and well-being of African Americans. Thus, particular emphasis in DEI is placed on addressing needs and concerns of traditionally underrepresented, underserved, and marginalized populations, of enhancing social welfare and pursuing broader goals of social justice. DEI represents a collection of methods and tools for use by organizations as well as a subject of scholarly inquiry. The purpose of this tutorial essay is threefold. First, we will explore the presence of DEI in the professional practice of operations research (OR), industrial engineering, management science, analytics, and other related fields (collectively referred to as OR/analytics). Second, we will examine the role of DEI in OR/analytics scholarship. Third, we will present an agenda for increased application of DEI principles in practice, scholarship, and service to the profession. This agenda will consist of specific practices in strategy, management, and operations that can improve organizations and the experiences of key stakeholder groups. It will also address suggestions for new and enhanced areas of scholarly inquiry to enlarge our conception of how, why, and under what conditions an increased focus on DEI can enhance social welfare and support efforts toward social and racial justice. This tutorial thus advances our understanding of ways that professions and disciplines associated with OR/analytics can use DEI to make our society more equitable, more just, and more welcoming of people from diverse backgrounds, identities, and communities.