This study aims to test the psychometric properties of the Malay, English, and Chinese 9-Item Shared Decision Making Questionnaire (SDM-Q-9) in breast cancer patients making treatment decisions. The original German SDM-Q-9 was translated to Malay using the back-translation method. A total of 222 newly diagnosed breast cancer patients making treatment decisions were sampled conveniently from three breast clinics between August 2015 and February 2016. A total of 66 patients answered the SDM-Q-9 in Malay, 87 in English, and 69 in Chinese. Data were analyzed using SPSS and AMOS software. SDM-Q-9 demonstrated good reliability in the three translations. All the items correlated well except for Item 1 in English. The factor loadings were within acceptable range except for Item 1 in Malay, Items 1 and 2 in English, and Items 7 and 9 in Chinese SDM-Q-9. However, no items were deleted in accordance with experts' opinions and the previous SDM-Q-9 validation studies. The Malay, English, and Chinese SDM-Q-9 demonstrated good reliability and validity.