Diabetic retinopathy (DR) is one of the most prevalent microvascular diabetic complications. Poor sleep health and obstructive sleep apnea (OSA) are risk factors for diabetes and poor glycemic control. Recent studies have suggested associations between poor sleep health/OSA and DR. Furthermore, there have been suggestions of melatonin dysregulation in the context of DR. We conducted a systematic review and meta-analysis exploring the associations between multidimensional sleep health (duration, satisfaction, efficiency, timing/regularity and alertness), OSA and melatonin with DR. Forty-two studies were included. Long, but not short sleep, was significantly associated with DR, OR 1.41 (95%CI 1.21, 1.64). Poor sleep satisfaction was also significantly associated with DR, OR 2.04 (1.41, 2.94). Sleep efficiency and alertness were not associated with DR, while the evidence on timing/regularity was scant. Having OSA was significantly associated with having DR, OR 1.34 (1.07, 1.69). Further, those with DR had significantly lower melatonin/melatonin metabolite levels than those without DR, standardized mean difference −0.94 (−1.44, −0.44). We explored whether treating OSA with continuous positive airway pressure (CPAP) led to improvement in DR (five studies). The results were mixed among studies, but potential benefits were observed in some. This review highlights the association between poor multidimensional sleep health and DR.