En este trabajo se exponen y comparan diferentes posturas teóricas que surgen de la operacionalización de las facetas del dominio Responsabilidad del Modelo de los Cinco Factores (FFM). La Responsabilidad refleja la capacidad de autorregulación de los sujetos, teniendo en cuenta tanto aspectos proactivos como inhibitorios de la conducta. Se realizaron comparaciones entre el modelo de seis facetas propuesto en el NEO-PI-R con operacionalizaciones que definen dos (Caprara et al., 2007), tres (Soto & John, 2016), cuatro (Taylor y DeBruin, 2006), cinco (Aguado et al., 2008) y hasta nueve facetas (Hofstee et al.,1992). Orden, Sentido del Deber y Autodisciplina son las facetas incluidas con mayor frecuencia en las operacionalizaciones de la Responsabilidad. Se advierten problemas de validez discriminante de las facetas, debido al solapamiento con otros dominios del MCF. Tal es el caso de Deliberación, cuyo contenido se vincula con Neuroticismo y su faceta de impulsividad. Algunos autores definen modelos más parsimoniosos con el fin de solucionar el problema del solapamiento y proponen dos facetas amplias que remiten a componentes de conductas proactivas e inhibitorias (Roberts et al., 2014). Se concluye sobre la necesidad de buscar una definición más completa de la Responsabilidad para alcanzar mayor utilidad descriptiva. Palabras clave Responsabilidad - Facetas - Cinco Grandes - Personalidad ABSTRACT THEORETICAL DIFFERENCES IN THE OPERATIONALISATION OF THE FACETS OF THE CONSCIENTIOUSNESS DOMAIN FROM THE BIG FIVE MODEL This paper presents and compares different theoretical positions arising from the operationalisation of the facets of the Conscientiousness domain from the Five Factor Model (FFM). Conscientiousness reflects the subjects’ capacity for self-regulation, taking into account both proactive and inhibitory aspects of behaviour. Comparisons were made between the six-facet model proposed in the NEO-PI-R with operationalisations defining two (Caprara et al., 2007), three (Soto & John, 2016), four (Taylor & DeBruin, 2006), five (Aguado et al., 2008) and up to nine facets (Hofstee et al.,1992). Order, Sense of Duty and Self-discipline are the most frequently included facets in the operationalisations of Conscientiousness.There are problems of discriminant validity of the facets due to overlap with other domains of the MCF. Such is the case of Deliberation, whose content is linked to Neuroticism and its facet of impulsivity. Some authors define more parsimonious models in order to solve the problem of overlap and propose two broad facets that refer to components of proactive and inhibitory behaviours (Roberts et al., 2014). It is concluded that a more comprehensive definition of Conscientiousness needs to be sought in order to achieve greater descriptive utility. Keywords Conscientiousness - Facets - Big Five - Personality