Atopic dermatitis is a common chronic inflammatory skin disease commonly found in primary care worldwide. It is characterized by erythematous, eczematous, intense pruritic skin lesions that usually come and goes. The evolution of atopic dermatitis and its management remains difficult to appreciate over the years as its various aspects have been changing over the decades. To produce a standard quality of care, medical practitioners must be able not only to recognize the disease but also how to apply this knowledge into their practices. Therefore, this study aims to describe the development, validation, and reliability of a questionnaire assessing atopic dermatitis recognition and management behaviors among Thai medical practitioners. The questionnaire was developed into a set of 35 questions divided into two major sections, disease recognition, and management behavior. The content validity was examined by a panel of five experts, and item-objective congruence (IOC) was then calculated. Internal consistency reliability was assessed using Cronbach’s alpha coefficient whereas Test-retest reliability was conducted using Pearson’s correlation coefficient. The overall test item-objective congruence (IOC) was acceptable (0.91). The overall questionnaire Cronbach’s alpha coefficients were good (0.87), and the overall questionnaire Pearson’s correlation coefficient was very high (0.92). Our study’s result proved that the questionnaire on atopic dermatitis was a valid and reliable tool to assess the sub-population ability to recognized and manage the disease.