We consider to what extent authenticity is related but distinct from Gray's (1982, 1985) behavioural inhibition/approach systems and Cloninger's psychobiological model (Cloninger, Svrakic, & Przybeck, 1993). Five-hundred and fifty-four adults (250 males, 304 females) completed measures of authenticity (Wood, Linley, Maltby, Baliousis, & Joseph, 2008), behavioural inhibition/activation (BIS/BAS, Carver & White, 1994) and Cloninger's temperament and character inventory (TCI-IPIP, Goldberg et al., 2006). Significant, small to moderate correlations are reported between authenticity and inhibitory and approach dimensions of Gray's and Cloninger's models. The directions of these relationships are consistent with Horney's (1945, 1951), and Maslow's (1954) descriptions of authenticity. However, dimensions of both Gray's and Cloninger's domains account for only a small 5.7-18% of the shared variance in authenticity, suggesting that authenticity is related but distinct from Gray's and Cloninger's personality dimensions.