The aim of this mixed methods systematic review was to synthesize contemporary evidence on effectiveness of community-based allied health (AH) services on acute care utilizations and views from relevant stakeholders. An a priori protocol was registered with PROSPERO [CRD42023437013]. Inclusion criteria were: (a) stand-alone interventions led by practitioners/graduates from one or more target AH professions (audiology, exercise physiology, diabetes educator, nutrition and dietetics, occupational therapy, physiotherapy, podiatry, psychology, social work, and speech pathology); (b) examined acute care utilization-related outcomes with/without perceptions of relevant stakeholders; and (c) published after 2010 and in English. Eligible studies were identified from: (a) bibliographic databases (MEDLINE, Embase, EmCare, PsycINFO, CINAHL complete, and the Cochrane Library) (September 19, 2023); (b) online databases (ProQuest Central and ProQuest Dissertations & Theses Global) and theses repository (Trove) (September 20, 2023); (c) Google and Google Scholar (October 17–18, 2023); and (d) citation searching. A modified version of McMaster Critical Appraisal Tools and McGill Mixed Methods Appraisal Tool were used to assess methodological quality. Data synthesis was through convergent segregated approach. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation. There were 67 included papers. The integrated quantitative and qualitative findings demonstrated mixed evidence, likely influenced by the heterogeneity of the evidence base, for the effectiveness of AH services on acute care utilizations. Patients and their carers were largely positive about these services, highlighting opportunities to build on these experiences. The certainty of evidence for patient-important outcomes was however “very low”, emphasizing cautious interpretation. The findings of this review shed light on the breadth and scope of AH in the community sector, and its potential impact on the acute sector. Further investment in, and ongoing research on, community-based AH can strengthen primary healthcare and relieve pressure on the acute sector.