The current diagnostic systems for mental health disorders are categorical, which, it has been argued, poorly reflect the reality of mental health problems. This is especially relevant in emotional disorders (EDs), especially due to the existing comorbidity between supposedly different disorders. To address this, Brown and Barlow developed a hybrid dimensional−categorical approach to EDs that can be evaluated with the Multidimensional Emotional Disorder Inventory (MEDI), a transdiagnostic self-report questionnaire. This study aims to adapt and explore the sources of validity evidence of the MEDI in a non-clinical sample of Spanish university students (n = 455). Two confirmatory analyses were performed: one with a four-dimensional structure obtained with an exploratory analysis and another with the original nine-dimensional structure of the MEDI. The latter obtained a better fit. The descriptive data, including percentiles, T-scores, and sex differences in total scores are also provided, together with sources of validity evidence. These revealed significant moderate interrelations between factors and with related measures (e.g., personality, depression, and anxiety). This study adapted the MEDI for use in Spanish, provides further support about its factor structure, and offers novel data about its validity sources. The MEDI makes the evaluation of dimensional and transdiagnostic models easier, which might be fundamental in present and future research and clinical practice.