Recent studies have posited that machine learning (ML) techniques accurately classify individuals with and without pain solely based on neuroimaging data. These studies claim that self-report is unreliable, making “objective” neuroimaging classification methods imperative. However, the relative performance of ML on neuroimaging and self-report data has not been compared. This study used commonly reported ML algorithms to measure differences between “objective” neuroimaging data and “subjective” self-report (i.e., mood and pain intensity) in their ability to discriminate between individuals with and without chronic pain. Structural MRI data from 26 individuals (14 individuals with fibromyalgia, 12 healthy controls) were processed to derive volumes from 56 brain regions per person. Self-report data included visual analog scale ratings for pain intensity and mood (i.e., anger, anxiety, depression, frustration, fear). Separate models representing brain volumes, mood ratings, and pain intensity ratings were estimated across several ML algorithms. Classification accuracy of brain volumes ranged from 53–76%, whereas mood and pain intensity ratings ranged from 79–96% and 83–96%, respectively. Overall, models derived from self-report data outperformed neuroimaging models by an average of 22%. Although neuroimaging clearly provides useful insights for understanding neural mechanisms underlying pain processing, self-report is reliable, accurate, and continues to be clinically vital.