Cancer-related fatigue (CRF) is one of the most commonly reported disease- and treatment-related side effects that impede quality of life. This systematic review and meta-analysis describes the effects of nutrition therapy on CRF and quality of life in people with cancer and cancer survivors. Studies were identified from four electronic databases until September 2017. Eligibility criteria included randomised trials in cancer patients and survivors; any structured dietary intervention describing quantities, proportions, varieties and frequencies of food groups or energy and macronutrient consumption targets; and measures of CRF and quality of life. Standardised mean differences (SMD) were pooled using random-effects models. The American Dietetic Association’s Evidence Analysis Library Quality Checklist for Primary Research was used to evaluate the methodological quality and risk of bias. A total of sixteen papers, of fifteen interventions, were included, comprising 1290 participants. Nutrition therapy offered no definitive effect on CRF (SMD 0·18 (95 % CI –0·02, 0·39)) or quality of life (SMD 0·07 (95 % CI –0·10, 0·24)). Preliminary evidence indicates plant-based dietary pattern nutrition therapy may benefit CRF (SMD 0·62 (95 % CI 0·10, 1·15)). Interventions using the patient-generated subjective global assessment tool and prescribing hypermetabolic energy and protein requirements may improve quality of life. However, the heterogeneity seen in study design, nutrition therapies, quality-of-life measures and cancer types impede definitive dietary recommendations to improve quality of life for cancer patients. There is insufficient evidence to determine the optimal nutrition care plan to improve CRF and/or quality of life in cancer patients and survivors.