COVID-19 led to an increase in online higher education courses. With this increase in demand, there needs to be online support to foster students' academic success. Online academic student support is often provided to students to assist them in developing the skills and knowledge to successfully complete their courses. However, it remains unclear whether online academic student support in higher education is successful, and if so, what makes it successful. This systematic literature review seeks to provide an overview of research on online academic student support in higher education. Out of 5385 initially identified publications from 2013 to 2022, 12 papers were included for review; seven studies were quantitative and five were mixed-methods studies. The synthesis of the findings reported outcomes on students' improved engagement, access to support and usage patterns, satisfaction, academic performance, motivation, creativity, self-efficacy, retention or course completion, and social benefits. This range creates a challenge for higher education providers who consider implementing best practice in the provision of online academic student support due to the diversity of approaches. Future research that is methodologically strong is needed to demonstrate the impact of online academic student support detailing how higher education providers can improve the quality, learning outcomes, and retention of students.