The time cut-off for primary closure of acute wounds is not clearly defined in the literature or in the surgical textbooks. It is even unclear whether the wound age increases wound infection rate. The scarcity of scientific evidence may explain the diverse wound management practices. To give guidance for further research in the field, this systematic review assessed recent evidence on the impact of wound age on the infection rate and on the selection of wound closure method. Using predefined criteria, we systematically searched Cochrane Central Register of Controlled Trials/CENTRAL, Cochrane Database of Systematic Reviews, MEDLINE, Scopus, Web of Science Core Collection, Current Contents, SciELO Citation Index, KCI-Korean Journal Database, Russian Science Citation Index, BIOSIS Citation Index, Data Citation Index, LILACS/Latin American and Caribbean Health Sciences Literature, and African Index Medicus; as well as online trial registries: ClinicalTrials.gov, WHO International Clinical Trials Registry Platform/WHO ICTRP, and CenterWatch. Nine studies met the selection criteria and were included in the review. This review could not establish the time frame for primary closure of wounds. The time intervals mentioned in many surgical textbooks were supported by only a few low-quality studies. More important factors to be considered when delaying primary closure of acute wounds were the history of diabetes, wound location, wound length, and the presence of a foreign body.