Purpose: Repetitive negative thinking (RNT) is the process of engaging in negatively valenced and habitual thought patterns. RNT is strongly associated with mental health conditions and often affects quality of life. This study explored RNT in older school-age children and adolescents who stutter to quantify the relationship between RNT and self-reported anxiety characteristics. An additional aim was to describe how individual differences in an adolescent's goal when speaking influences the frequency they engage in RNT. Method: Ninety-nine children and adolescents who stutter aged 9-18 years completed a measurement of the frequency/severity of RNT, a screener of anxiety characteristics, and a measure of adverse impact related to stuttering. Children aged 10 years and above also answered questions about their goal when speaking. Results: Individual differences in RNT significantly predicted Overall Assessment of the Speaker's Experience of Stuttering (OASES) Total Scores more so than a child or adolescent's age. Higher generalized or social anxiety scores were significantly correlated with more frequent RNT and higher OASES Total Scores. Individual differences in goal when speaking (i.e., whether or not to stutter openly) were found to predict RNT. Finally, 22 children and adolescents (22.2%) also screened positive for generalized anxiety disorder and 32 (32.3%) screened positive for social anxiety disorder. Discussion: These data provide strong evidence that: (a) many children and adolescents who stutter engage in RNT; (b) children and adolescents who engage more frequently in RNT or who have higher OASES Total Scores may be at increased risk for more characteristics of generalized or social anxiety; and (c) individual differences in goal when speaking can predict the degree to which an adolescent engages in RNT.