Background: Knowledge about sleep complaints of caregivers of patients with Alzheimer’s disease (AD) and Parkinson’s disease (PD) is limited, and we lack information about the relationship between caregivers’ sleep problems and their quality of life (QoL). Methods: We evaluated subjective sleep quality and its relationship to QoL in a group of 80 caregivers of patients with AD (ADCG, n = 40) and PD (PDCG, n = 40), and in 150 controls. Information about nighttime complaints was collected using the Pittsburgh Sleep Quality Index (PSQI). QoL was measured using the McGill QoL Questionnaire. Results: Eighteen ADCG (45%), 22 PDCG (55%), and 45 (30%) controls reported poor sleep quality. Mean global PSQI score of PDCG (6.25 ± 3.9) was not significantly different from that of ADCG (5.8 ± 3.5; p = 0.67). However, both PDCG and ADCG scored significantly higher than control group (4.3 ± 3.1; p < 0.01). ADCG frequently reported difficulties falling asleep (72.5%) and disturbed sleep (100%). PDCG reported reduced subjective sleep quality (80%) and increased sleep disturbances (100%). Poor sleep quality was associated with depressive symptoms and correlated with QoL in caregivers of both groups, particularly the psychological symptoms domain. Conclusions: Among caregivers of patients with AD and PD, poor sleep quality is frequent and significantly linked to QoL and depressive symptoms. Identifying the nature of sleep disturbances not only in patients but also in their caregivers is important as appropriate treatment may lead to a better management of the needs of families coping with these patients.