This article describes the development and validation of the Gastrointestinal Unhelpful Thinking scale. The purpose of the research was to develop the Gastrointestinal Unhelpful Thinking scale to assess in tandem the primary cognitiveaffective drivers of brain-gut dysregulation, gastrointestinal-specific visceral anxiety, and pain catastrophizing. The research involved 3 phases which included undergraduate and community samples. In the first phase, an exploratory factor analysis revealed a 15-item 2-factor (visceral sensitivity and pain catastrophizing) scale (N = 323), which then was confirmed in the second phase: N = 399, χ²(26) = 2.08, p = .001, Tucker-Lewis Index = 0.94, comparative fit index = 0.96, standardized root mean square residual = 0.05, and root mean square error of approximation = 0.07. Demonstrating convergent validity, Gastrointestinal Unhelpful Thinking scale total and subscales were strongly correlated with the modified Manitoba Index, Irritable Bowel Syndrome Symptom Severity Scale scores, Visceral Sensitivity Index, and the Pain Catastrophizing Scale. A third phase (N = 16) established test-retest reliability for the Gastrointestinal Unhelpful Thinking scale (total and subscales). The test-retest reliability correlation coefficient for the Gastrointestinal Unhelpful Thinking scale total score was .93 (p < .001) and for the subscales was .86 (p < .001) and .94 (p < .001), respectively. The Gastrointestinal Unhelpful Thinking scale is a brief psychometrically valid measure of visceral anxiety and pain catastrophizing that can be useful for both clinicians and researchers who wish to measure these thinking patterns and relate them to changes in gastrointestinal and psychological symptoms.