Background Habitual caffeine consumers who abstain from caffeine experience withdrawal symptoms such as headache, fatigue, difficulty concentrating, mood disturbances, and flu-like symptoms (Juliano and Griffiths, 2004). The caffeine withdrawal syndrome has been documented across many experimental studies; however, little is known about how withdrawal symptoms co-vary during a discrete episode. Furthermore, a validated measure of caffeine withdrawal is lacking. Objective To develop, evaluate, and reduce a 23-item measure of caffeine withdrawal symptoms; the Caffeine Withdrawal Symptom Questionnaire (CWSQ), to a set of composite variables. Methods Caffeine consumers (N = 213) completed the CWSQ after 16 h of caffeine abstinence. A subset of participants also completed the CWSQ during a preceding baseline period and/or after double-blind consumption of caffeinated coffee. Results Principal components analysis resulted in a solution comprised of 7-factors: 1. Fatigue/drowsiness; 2. Low alertness/difficulty concentrating; 3. Mood disturbances; 4. Low sociability/motivation to work; 5. Nausea/upset stomach; 6. Flu-like feelings; and 7. Headache. With the exception of nausea/upset stomach, the CWSQ total score and individual composite scores were significantly greater during caffeine abstinence relative to both baseline and double-blind consumption of caffeinated coffee, thereby demonstrating sensitivity of the measure. Compared to non-daily coffee consumers, daily consumers had greater increases in total withdrawal, fatigue/drowsiness, low alertness/difficulty concentrating, mood disturbances, and headache. Conclusions Future directions include replication, assessment on a clinical population, and further examination of psychometric properties of the CWSQ. The CWSQ should facilitate the assessment and diagnosis of caffeine withdrawal and increase our knowledge of the caffeine withdrawal syndrome.