This CSV data file comprises data from 106 persons with MS that participated in the RCT "Training and Energy Management Education to Improve Quality of Life in Persons With Multiple Sclerosis" (ClinicalTrials.gov Identifier: NCT04356248), which was performed in Valens rehabilitation clinic, Valens, Switzerland. Data have been collected between 13 July 2020 and 11 May 2022. Cross-sectional data include anthropometric, demographic, and disease-related data as well as kynurenine pathway (KP) metabolic data. Kynurenine pathway (KP) metabolic data have been obtained by targeted metabolomics at Bevital AS, Bergen, Norway. Within a cross-sectional analysis, associations of body mass index (BMI)-classified overweight and obesity with KP metabolite concentrations have been calculated using bivariate correlation analyses and ANCOVAs. Results have been presented in the original article entitled "The Serum Kynurenine Pathway Metabolic Profile is Associated with Overweight and Obesity in Multiple Sclerosis" (DOI:https://doi.org/10.1016/j.msard.2023.104592).