OBJECTIVE: Obstructive events in patients with obstructive sleep apnoea (OSA) cause recurrent sleep fragmentation and occasional desaturation, which can cause various parasomnias, including nightmares. Several lines of evidence suggest that OSA may be potentially associated with a higher frequency of nightmares. METHOD: We searched for studies published from January 2000 until November 2020 in PubMed, the Cochrane Library, Web of Science and Google Scholar. The keywords Obstructive Sleep Apnoea / OSA / Nightmares / CPAP / PTSD / Sleep Quality / Dream / were used in various combinations. The literature search identified 1361 articles which were eligible to more careful examination. Secondary texts were also examined, evaluated for suitability, and added to the primary document list. Finally, a total of 168 articles were included in the review. RESULTS: According to current findings, OSA could affect emotional regulation via activation of limbic system during sympathetic activation and suppression of REM sleep essential to emotional regulation. The reviews also found an increased prevalence of nightmares in OSA patients. OSA is significantly associated with psychiatric morbidity, as was proved in several studies. There seems to be a strong link between nightmares, OSA, PTSD symptoms and other disorder such as unipolar depression. CONCLUSIONS: It is clear that therapy of OSA patients, especially those with psychiatric comorbidity, must be complex. In the case of nightmares, we should not forget to use psychotherapy as a first choice, particularly in patients with poor compliance to continuous positive airway pressure (CPAP) and poor sleep and overall life quality. In the same time, we should emphasise the healthy lifestyle and sleep hygiene.