The role of assistants to complement the work of fully qualified practitioners has been recognised, however, there remains a lack of research (Collyer, 2012) relevant to the current context of service delivery of educational psychology services (EPSs), including the commissioning of services and demands for EPSs. Paper One used A Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework (Moher, Liberati, Tetzlaff & Altman, 2009) to search, screen and identify research relevant to psychology paraprofessionals. An exploratory multiple embedded case study was conducted across two local authorities in England (Paper Two). Participants included five assistants, 12 educational psychologists (EPs), and four senior/principal EPs. Focus groups and group interviews were completed using semi-structured interview schedules. Transcriptions were analysed using Braun and Clarke’s (2006) thematic analysis to draw cross case conclusions. Seven relevant studies were reviewed and synthesized in Paper One to find that within clinical and educational psychology, assistants are used in a variety of ways, completing discrete tasks, or working in conjunction with fully qualified psychologists to extend psychological input. Across the two cases, the rationale for employment was due to difficulties recruiting fully qualified EPs and the interrelationship of function was explored along with the benefits and challenges to the deployment of assistants. Both papers found that assistants contribute to service level developments and work directly with service users. Key features to facilitate the successful deployment of assistants included training and supervision. Employment as an assistant was associated with career progression onto professional training. Implications of findings are considered in relation to practice in Paper Three and the findings dissemination strategy includes; the publication of both studies; presentation of the research to participants; the circulation of a summary to principal EPs; and presenting the research at a practitioner conference.