BACKGROUND: Competitive integrated employment often remains out of reach for people with intellectual disability. Consistently poor outcomes have resulted in research and policies promoting employment through the provision of workplace supports. Researchers have established a substantial body of intervention research addressing pre-employment supports. However, minimal intervention research exists addressing the provision of supports subsequent to job placement. OBJECTIVE: The objective of this study was to systematically examine the body of intervention research associated with workplace supports used to address career maintenance and career advancement for employees with intellectual disability. METHODS: A systematic literature review was conducted, examining intervention research published between 1984 and 2018. Fourteen studies met inclusion criteria. These studies included 85 employees with intellectual disability and 57 support providers (e.g., employment specialists, job coaches, co-workers). RESULTS: Results revealed evidence of interventions addressing career maintenance through the provision of training to both support providers and employees with intellectual disability. Training addressed workplace performance and social integration. No interventions were identified promoting career advancement. CONCLUSION: This paper offers an overview of the current intervention research base addressing workplace supports for employees with intellectual disability and makes recommendations for research, policy, and practice. [ABSTRACT FROM AUTHOR]