Abstract Objective The aim of the present systematic review is to assess the prevalence and severity of and distress caused by xerostomia over time in adult hematopoietic stem cell transplantation (HSCT) recipients. Methods PubMed, Embase, and the Cochrane Library were searched for papers published between January 2000 and May 2022. Clinical studies were included if patient-reported subjective oral dryness was reported in adult autologous or allogeneic HSCT recipients. Risk of bias was assessed according to a quality grading strategy published by the oral care study group of the MASCC/ISOO, resulting in a score between 0 (highest risk of bias) and 10 (lowest risk of bias). Separate analysis focused on autologous HSCT recipients, allogeneic HSCT recipients receiving a myeloablative conditioning (MAC), and those receiving a reduced intensity conditioning (RIC). Results Searches yielded 1792 unique records; 22 studies met the inclusion criteria. The quality scores ranged between 1 and 7, with a median score of 4. The prevalence, severity, and distress of xerostomia increased shortly after HSCT. Severity of xerostomia in allogeneic MAC recipients was higher compared to allogeneic RIC recipients 2–5 months post-HSCT (mean difference: 18 points on 0–100 scale, 95% CI: 9–27); after 1–2 years, there was no significant difference anymore. Conclusion The prevalence of xerostomia in HSCT recipients is high in comparison to the general population. The severity of complaints is raised during the first year post-HSCT. The intensity of the conditioning plays a key role in the short-term development of xerostomia, while factors affecting the recovery in the long term remain largely unknown.