Background:
     
     Essential services ensure the health, safety, and well-being of individuals and their communities. However, there is currently a lack of consensus on what constitutes an essential service in Australia. This gap hinders a detailed spatial understanding of essential service provision, access, and influence on populations. This systematic review critically assessed the literature on essential services and their impact on quality of life to understand service definitions and their relative contributions to quality of life.
   

Methods:
     
     A systematic search of ten databases was undertaken following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology. Five criteria were established for the inclusion of studies: (i) major developed economies, (ii) defined essential service and focus on spatial access, (iii) quality of life outcome, (iv) peer-reviewed, and (v) published between 2000 and 2024.
   

Results:
     
     From 1,473 unique records, seven studies met the inclusion criteria, with studies from Europe, Asia-Pacific, and North America. Across the studies, services were characterised based on their primary function and contributions to quality of life. Service categories included food, retail, personal services, health, education, culture and recreation, and faith-based services. Despite demographic and scale variations, services that fostered social connection and a sense of place showed the highest positive impact on quality of life.
   

Conclusions:
     
     Findings indicate limited and inconsistent evidence on essential service measures and their relationship with quality of life. The persistent lack of justification for classifying services as essential in research hinders definitive conclusions about which services most effectively enhance quality of life. Future research should adopt standardised, validated measures, and address representation gaps across diverse populations and regions. This work is fundamental for developing a validated set of essential services, to improve national modelling of geographic access and inform policy, decision-making, and understanding of how access to services influences quality of life.