Professional development programs (PDs) for in-service teachers are usually structured to deliver standardized content. However, considering the differences in the teaching practices utilized by teachers of different subjects, their needs and expectations may vary. Thus, this study develops an instrument to determine inservice teachers' expectations regarding PDs. Themes regarding the PD expectations of teachers were created based on a detailed literature review and authors' field experiences. In line with these themes, an item pool comprising 51 items was created. The developed instrument was applied online to 322 teachers from different provinces of Turkey and teaching different subjects. Exploratory factor analysis was performed on the dataset to ascertain the construct validity of the instrument. As a result of the analyses, the finalized instrument comprised 49 items and 6 dimensions; support, practice, learning, student success, organization, and career. The Cronbach's alpha internal reliability coefficient of all items in the finalized instrument was .94. These findings show that the instrument is a valid and reliable data collection tool for determining teacher expectations of PDs for identified themes. This instrument will be particularly useful in exploring the expectations of teachers while designing PDs and determining the extent to which current PDs meet teachers' expectations.