Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources including networks, servers, applications, and services. Our aim in this study was to develop and validate an instrument to investigate the determinants of cloud computing services (CCSs) based on Theory of Planned Behavior (TPB). A total of 240 faculty members in a medical university participated in this cross-sectional study. The development of the Theory of Planned Behavior-Cloud Computing Services use Questionnaire (TPB-CCSQ) began with a comprehensive review of literature. Content and construct validity, feasibility? as well as reliability were assessed. Exploratory factor analysis indicated an optimal reduced solution with 30 items and 5 factors. The factors identified included Attitude toward CCSs use, Perceived Privacy/Security, Perceived Behavioral Control, Intention to use CCSs and Subjective Norms. The measurement model was found to be with a good fit to the data in the assumed model, and all sub-scales were found to be significant within an acceptable range. Our findings demonstrated validity, reliability, simplicity and functionality of the TPB-CCSQ. Information technology researchers, community agencies and educational organizations delivering CCSs may apply this instrument as a practical and useful tool to investigate the cognitive determinants of CCSs.