Introduction: Fatigue is one of the most common and disabling symptoms for people with multiple sclerosis. Its assessment is complicated due to inconsistent and vague terms used to define fatigue, and because it is highly task-dependent. A new fatigue taxonomy was proposed, whereby fatigue is described and treated as two different constructs: perceived fatigue (i.e. subjective perception of reduced capacity) and performance fatigability. Purpose: To investigate how perceived fatigue and performance fatigability have been assessed in people with multiple sclerosis and to examine the relationship between perceived fatigue and performance fatigability in people with multiple sclerosis using literature review. Methods: A review of the literature published until May 2019 was performed. We used databases PubMed and Cochrane Library to identify appropriate studies which assessed both perceived fatigue as well as performance fatigability in people with multiple sclerosis. Results: Eleven studies were included in this literature review. Seven different self-reporting scales were used to assess perceived fatigue, and 6-minute walking test (six), muscle performance tests (three), or both (two studies) were used to measure performance fatigability. Six studies found a statistically significant, but not high correlation (r range from –0,14 to –0,66) between perceived fatigue and performance fatigability. No statistically significant correlation was found in other five studies. Conclusions: There is statistically significant but weak association between perceived fatigue and performance fatigability in people with multiple sclerosis. They need to be assessed separately using established test protocols. Factors such as depression, clinical disability, type of multiple sclerosis, and duration of illness may influence the relationship as well. Agreeing on one or more fatigability assessment tasks could reduce the variability of results in future research. More research is needed to test the validity and reliability of new potential tests for performance fatigability in people with multiple sclerosis.