Background Post-stroke pneumonia and other infectious complications are serious conditions whose frequency varies widely across studies. Aims We conducted a systematic review to estimate the frequency of post-stroke pneumonia and other types of major infection. Summary of review MEDLINE, EMBASE, CINAHL, and PsycINFO databases were searched for prospective studies with consecutive recruitment of stroke patients. The primary outcome was post-stroke pneumonia. Secondary outcomes were any infection and urinary tract infection. Quality assessment was done using Newcastle Ottawa scale. Heterogeneity of estimates across study populations was calculated using Cochran's Q (heterogeneity χ²) and I² statistics. A total of 47 studies (139,432 patients) with 48 sample populations were eligible for inclusion. Mean age of patients was 68.3 years and their mean National Institute of Health Stroke Scale score was 8.2. The pooled frequency of post-stroke pneumonia was 12.3% (95% confidence interval [CI] 11%–13.6%; I² = 98%). The pooled frequency from 2011 to 2017 was 13.5% (95% CI 11.8%–15.3%; I² = 98%) and comparable with earlier periods (P interaction = 0.31). The pooled frequency in studies in stroke units was 8% (95% CI 7.1%–9%; I² = 78%) and significantly lower than other locations (P interaction = 0.001). The pooled frequency of post-stroke infection was 21% (95% CI 13%–29.3%; I² = 99%) and of post-stroke urinary tract infection was 7.9% (95% CI 6.7%–9.3%; I² = 96%). Conclusion Approximately 1 in 10 stroke patients experience pneumonia during the acute period of hospital care. The frequency of post-stroke pneumonia has remained stable in recent decades but is lower in patients receiving stroke unit care compared to management in other ward settings.