Inner speech is frequently assessed using self-report scales, but their validity is understudied. Uttl et al. (2011) found moderate correlations, perhaps because measures tap into different dimensions of inner speech. We expand on these preliminary results by investigating reliability and concurrent validity of seven inner speech questionnaires in a larger sample. Our results indicate that inner speech questionnaires are reliable but hold moderate concurrent validity, in line with Uttl and colleagues’ (2011) results. Specifically, our results suggest that some inner speech scales may capture a general conception of inner speech, while others may assess evaluative components of negative self-talk, self-regulation, and self-reflective processes, but not emotional valence. The results hold implications around further validity investigations of inner speech measures.