Recent research suggests that repetitive negative thinking is a transdiagnostic phenomenon that is present across affective disorders. Notably, multiple measures of repetitive negative thinking exist, including some that are disorder-specific and others that are transdiagnostic. To date, no studies have examined whether these measures are captured by a latent Repetitive Negative Thinking factor or how these measures are differentially associated with symptoms of affective disorders, including mood, anxiety, and obsessive-compulsive spectrum disorders. Across two separate studies, Mechanical Turk participants completed measures of rumination, post-event processing, dampening of positive affect, and two transdiagnostic measures of repetitive thinking, as well as measures of depression, physiological anxiety, social anxiety, obsessive-compulsive disorder, and body dysmorphic disorder. Using structural equation modeling, evidence of a single Repetitive Negative Thinking latent factor was found. Moreover, positive associations emerged between the latent factor and all five clinical symptom measures. Notably, few differences emerged in the magnitude of the associations between measures of repetitive negative thinking and psychological symptoms. Together, findings support a transdiagnostic conceptualization of repetitive negative thinking.