Background: One of the most common interpersonal reactions to threat and anxiety is to seek reassurance from a trusted person. The Reassurance Seeking Questionnaire (ReSQ) measures several key aspects of reassurance seeking behaviour, including frequency, trust of sources, intensity, carefulness, and the emotional consequences of reassurance seeking. Aims: The current study compares patterns and consequences of reassurance seeking in obsessive-compulsive disorder (OCD) and depression. Method: ReSQ scores were compared for three groups: 32 individuals with OCD, 17 individuals with depression, and 24 healthy comparison participants. Results: We found that individuals with OCD tended to seek reassurance more intensely and employ self-reassurance more frequently than individuals with depression or healthy participants, and that if reassurance was not provided, they tended to feel a greater urge to seek additional reassurance. Conclusions: This study is the first to quantitatively elucidate differences in reassurance seeking between OCD and depression.