Background This study aimed to explore the relationship between cancer‐related fatigue (CRF) and personality in patients with breast cancer after chemotherapy. Methods A cross‐sectional study was conducted to study the relationship between CRF and personality in breast cancer patients after chemotherapy. CRF and personality were measured by the cancer fatigue score and the Eysenck Personality Questionnaire, respectively. Results A total of 300 breast cancer patients who had received chemotherapy were recruited to this study. Eysenck Personality Questionnaire scores of psychoticism, introversion, and extroversion in the patients were lower than the norm level (p < 0.01), but those of neuroticism and lie were higher than the norm level (p < 0.01). Multivariate analyses showed positive correlation between psychoticism and affective fatigue, neuroticism and total fatigue, and physical fatigue and cognitive fatigue. Multivariate analyses also showed negative correlation between introversion or extroversion and total fatigue, physical fatigue or affective fatigue, and lie and total fatigue or cognitive fatigue. Conclusions There was CRF in patients with breast cancer after chemotherapy. Psychoticism, extroversion/introversion, neuroticism, and lie are correlated with CRF in breast cancer patients after chemotherapy. Copyright © 2013 John Wiley & Sons, Ltd.