Social rank theory suggests that mood variation is linked to the security a person feels in his/her social domain and the extent to which they are sensitive to involuntary subordination (e.g. feeling defeated and feeling inferior). Previous studies looking at rank-related and competitive behaviour have often focused on striving for dominance, whereas social rank theory has focused on striving to avoid inferiority. This study set out to develop a measure of ‘Striving to Avoid Inferiority’ (SAIS) and assess its relationship to other rank and mood-related variables. We hypothesized two factors: one we called insecure striving, relating to fear of rejection/criticism for ‘not keeping up’, and the second we called secure non-striving, relating to feeling socially acceptable and valued regardless of whether one succeeds or not. This scale was given to 207 undergraduates. The SAIS had good psychometric properties, with the two factors of insecure striving and secure non-striving strongly supported by exploratory factor analysis. Both factors were significantly (though contrastingly) related to various fears of rejection, need for validation, hypercompetitive attitudes, feeling inferior to others, submissive behaviour and indicators of stress, anxiety and depression. Striving to avoid inferiority was a significant predictor of psychopathologies, especially where individuals perceived themselves to have low social rank.