The goal of this study was to psychometrically evaluate the Multidimensional Assessment of Interoceptive Awareness (MAIA), a popular self-report questionnaire claimed to assess the most important subjective aspects of interoception. We collected data in two samples (N = 644 and N = 1,516) and focused on the factor structure and validity of MAIA, as well as its associations with personality traits. Confirmatory Factor Analysis suggested that six of the eight subscales measure a common general factor of self-reported interoception; two MAIA subscales, Not-Worrying and Not-Distracting were only weakly related to this factor. Whereas the general factor correlated strongly with a measure of perceived attentiveness to normal nonemotive body processes, and moderately with Extraversion, Openness and Conscientiousness, the Not-Worrying factor showed moderate to strong negative correlations with Emotionality, pain catastrophization, and anxiety-related aspects of body focus. Not-Distracting was only weakly associated with the validating scales. Overall, these findings do not support the claimed eight-factor structure of the MAIA but indicate the existence of an overarching general factor. Additionally, this study provides evidence that interoceptive awareness, as measured by the MAIA, is related to, but distinct from personality.