Objective: To develop and validate an oral anticoagulant knowledge tool for Chinese-speaking patients treated with warfarin or direct oral anticoagulants (DOACs) in Hong Kong. Method: This pilot validation study consisted of the following three phases: (1) the development of a knowledge tool and content validity assessment; (2) a pilot study of 200 participants, consisting of 100 patients taking warfarin or DOACs, 50 pharmacists, and 50 members of the general public; and (3) known-group validity and reliability assessments. Results: A 19-item “Chinese Oral Anticoagulants Knowledge Tool (C-OAKT)” was developed with a scale content validity index of 0.95. The mean score for known-group validity was significantly higher in the pharmacist group than the patient groups, and the patient groups scored significantly higher than the general public (mean ± standard deviation [SD] = 90.00 ± 7.11 vs. 51.55 ± 17.49 vs. 19.0 ± 15.42, respectively; p