Spousal cancer caregivers’ emotional and relational health can become compromised over time due to ongoing challenges related to the cancer experience. This warrants a call for the assessment of interventions aimed at improving aspects of caregiver well-being. The current study employed a randomized controlled trial to determine whether emotional disclosure via the use of expressive writing improved spousal cancer caregivers’ perceived caregiver burden, stress, and depression. Participants (N = 64) were assigned to one of the two disclosure conditions: expressive disclosure or benefit finding—or to a time-management control condition. Participants completed three at-home writing sessions at one-week intervals. Results indicated that written forms of emotional disclosure might improve burden, stress, and depression contingent on writing condition. Specifically, both forms of emotional disclosure outperformed the control condition in reducing caregivers’ depression. The control condition outperformed treatments in reducing caregiver stress. Finally, posttest caregiver burden was significantly lower than pretest burden across all writing conditions. This trial was registered with clinicaltrials.gov, ID: NCT02339870.