Objectives: To determine the magnetic resonance (MR) imaging features of localised giant cell tumour of the tendon sheath in fingers and to evaluate the preoperative diagnostic performance of MR imaging in assessment of the local tumour extent. Methods: Between January 2003 and December 2013, MR images of patients with surgically resected and histologically proven giant cell tumour of the tendon sheath in fingers in a regional hospital in Hong Kong were retrospectively reviewed. MR imaging appearance and local tumour extent-including invasion of tendon, bone, joint, and tenosynovial space-were evaluated and compared with surgical findings. Results: The MR signal intensity of giant cell tumour of the tendon sheath in fingers of 29 patients was consistently equal to or lower than that of skeletal muscle on T1-and T2-weighted images. More than half of the lesions (17 tumours, 58.6%) had a high signal intensity on T2-weighted images with fat suppression. All tumours demonstrated a variable degree of enhancement and almost all (12/13 tumours, 92.3%) demonstrated blooming artefacts. The local tumour extent with invasion of tendon, bone, joint, and tenosynovial spaces was consistent with surgical findings in most of the examined cases, with an accuracy of 100%, 93.1%, 100%, and 96.6%, respectively. The degree of tumour encasement of the tendon was the only statistically significant predictor for tenosynovial space invasion (odds ratio = 1.0; p = 0.008). All 29 cases were completely excised with no tumour recurrence after a mean follow-up of 3.4 years (standard deviation, 2.1 years; range, 0.6-8.0 years). Conclusion: Giant cell tumour of the tendon sheath in the fingers is characteristic on MR images. MR imaging can accurately assess the local tumour extent and may help preoperative surgical planning, enable complete resection, and reduce tumour recurrence.