ABSTRACT Background: Irritability, as a trans dimensional symptom, is present in several mental disorders. This study investigated the psychometric properties of the Spanish version of the Brief Irritability Test (BITe). Subjects and Methods: The recruitment has been performed through an online survey launched through common social media (Facebook, Twitter) and messaging apps (WhatsApp, Telegram) from 1st to 31st May 2022. Subjects included were individuals ≥18 years old of age of both sexes. 1920 individuals were rated for the validation analysis. The BITe has been translated into Spanish and validated through confirmatory factor analysis. Participants have been also scored with the Aggression Questionnaire (AQ). Results: Kaiser-Meyer-Olkin (KMO) test was adequate (KMO=0.880) and sphericity tested significantly (p<0.001). The confirmatory analysis confirmed that the scale is one-dimensional. The model adjustment was good, according to all fit indices. Cronbach’s alpha also confirmed an excellent internal consistency (α=0.91). Scores between the two scales (the BITe and the AQ) have shown a good convergence (r=0.512; p<0.001). Conclusions: The Spanish version of the BITe is a unidimensional scale of five Likert-type items that shows good internal validity and high reliability, which implies that this version has excellent psychometric properties for both male and female Spanish-speakers.