Occupational justice recognizes that all people have the right to occupational engagement because it is through occupational engagement that people experience well-being. Occupational injustice occurs when outside forces prevent people from engaging in occupation, require participation in activities that they find meaningless, or prevent people from making choices about their occupations. People with developmental disabilities in a day program are at risk for occupational injustice because they require environmental support in order to engage in occupation. This phenomenological study explored occupational engagement of adults with moderate to severe disabilities in a day program by examining what the staff members and consumers found meaningful within the program activities and capturing how the consumers exhibited occupational engagement. This study understood occupational engagement in terms of meaning, self-choice, and motivation leading to involvement in occupation. The methods involved phenomenological interviews with 10 staff members regarding satisfying and dissatisfying experiences working with the consumers, interviews with 10 consumers with moderate to severe developmental disabilities regarding the activity groups using visual supports to enable participation, and four observations of consumers in preferred and less preferred activity groups using the Volitional Questionnaire. Strategies were employed to ensure trustworthiness of the data and analysis including dense description, data triangulation, member checks, peer review, reflexive journaling, and the use of a structured observation tool with demonstrated reliability and validity. Thematic analysis demonstrated that staff members found meaning in the day program activities through Consumer Engagement in Program Activities and Reciprocal Interaction, and the consumers found meaning in the day program activities through Doing/Active Engagement and Respectful Interaction. The consumers demonstrated occupational engagement through the following themes: Doing Activity/Initiating Action, Positive Affect, and Focused Attention. The findings demonstrated the influence of a supportive environment, choice, and relationships between consumers and staff members that may be reflective of co-occupation on occupational engagement. This information is important in order to build the body of knowledge regarding occupational engagement in an infrequently studied population, understand the implications related to such persons' occupational justice, and include the perspectives of people with moderate to severe cognitive disabilities in the study of occupation.