Background: Fear of incontinence is an understudied anxiety associated with significant distress and impairments. The Fear of Incontinence Questionnaire (FOIQ) was previously developed, but further examination of its psychometric properties is necessary. This study aimed to 1) examine the factor structure, internal consistency, convergent validity and test-retest reliability of the FOIQ and 2) explore the mediational role of avoidance in the relationship between fear of incontinence and depressive symptoms. Method: Cross-sectional data were collected using an online questionnaire assessing demographics, mood and fear of incontinence from 362 adults aged between 18-91 years. The FOIQ was completed again by 143 participants 2 weeks later. These data were combined with an existing dataset of people with fear of incontinence (n = 434) to form a larger dataset (n = 796). Results: Exploratory factor analysis of a 16-item version of the FOIQ revealed a three-factor structure. The FOIQ and its three subscales were found to have good internal consistency: full scale (α = .91), Avoidance/Impact (α = .90), Safety behaviours/Catastrophising (α = .83), and Disgust/Shame (α = .81). The full scale showed satisfactory test-retest reliability (ICC = .85), with similar ICCs for the three subscales (.79 to .87). The FOIQ showed appropriate convergent validity with other related constructs. Mediation analyses indicated that avoidance partially mediated, but accounted for a small amount of variance (2%) in the relationship between fear of incontinence and depressive symptoms after controlling for age, general anxiety and subjective health. Conclusions: This study suggests that the FOIQ is a reliable and valid measure of fear of incontinence. Avoidance was found to be a partial mediator but had limited predictive value for the relationship between fear of incontinence and depressive symptoms.