Aim(s)To identify and synthesize evidence available on nurse leaders' interpersonal communication competence.DesignSystematic mixed‐methods review according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis checklist.MethodsThe data were collected following predefined inclusion criteria. Two authors independently performed the study selection using Covidence software. Three authors assessed the quality using Joanna Briggs' Institute's critical appraisal tool and the mixed‐methods appraisal tool. The data‐based convergent synthesis design and narrative synthesis were used.Data SourcesCINAHL, PubMed, Scopus, Business Source Elite, Academic Search Premier, Communication & Mass Media Complete, PsycInfo, Web of Sciences, Medic and Finna.fi were searched and the screening of citations in relevant articles. The final searches were performed on 17 October 2022.ResultsA total of 26 studies—15 quantitative, 9 qualitative and 1 of both mixed‐method and multi‐method—met the inclusion criteria. The nurse leaders' interpersonal communication competences described in the extant literature were categorized into three themes: message competence, relational competence and task competence. There were considerable differences in the levels of competence, as some competences were considered basic communication skills, while others required more advanced level competences. Furthermore, three competence levels were identified: novice, competent and expert.ConclusionsThis study unravels a unique hierarchical description of communication skills across competence categories, supported by the assumption that communication skills are structured hierarchically. The studies reviewed herein had a narrow perception of nurse leaders' interpersonal communication competence and indicated a transmissional understanding of communication.ImpactThis is the first mixed‐methods systematic review that describes and synthesizes the evidence on nurse leaders' communication competencies hierarchically and across competence levels. The study suggests that further research should focus on a broader and more analytical understanding of the cognitive and affective aspects of interpersonal communication competence.PROSPERO IDCRD42023385058.Patient or Public ContributionNo patient or public contribution.