Increasing numbers of people are working part-time (PT) hours, sometimes involuntarily (IPT). Australia has the fourth highest percentage of PT employees among Organization for Economic Co-operation and Development countries (26%). This study examines relationships between work design factors and workplace inclusion for PT employees and identifies how perceived inclusion and work engagement of PT and IPT employees compares with full-time (FT) employees. Data were collected using an online questionnaire distributed to employees in Australia. A part-time work design model was developed and tested across two independent samples using partial least squares. Results suggest that PT and IPT employees feel less included in the workplace compared to FT employees. PT employees also perceive their roles to be less task interdependent. A key finding was that PT employees' perceived inclusion was related to proactive behaviors, autonomy, and job crafting, in addition to hours worked. Implications for the management of PT employees are discussed.