Background: Wood’s lamp examination is a useful diagnostic test in many dermatological disorders. However, there was limited data on knowledge of physicians about this tool. Objective: To evaluate basic knowledge of physicians on Wood’s lamp and its applications. Methods: The study used questionnaires in Thai general physicians who attended the 2013 Dermatology Annual Meeting. The questionnaire composed of a picture of a Wood’s lamp instrument and two open-end questions including 1) What is the name of this device? 2) Which diseases can this device help to make the diagnosis? Results: Eighty-two physicians enrolled in this study. Only 55 physicians (67.1%) answered the name of a Wood’s lamp correctly. There were 29 out of 55 physicians (52.7%) knew at least one application of Wood’s lamp. About half did not know any applications. Tinea versicolor, followed by melasma, tinea captitis, erythrasma, acne, porphyria, and vitiligo, respectively were the common applications that most physicians answered. Conclusion: This study showed around two-third of physicians know Wood’s lamp, but only half of them were knowledgeable about its’ application in dermatoses. Education regarding Wood’s lamp and application should be emphasized more in physicians to assist in dermatologic diagnoses.