*Result*: Questionnaire of Approach and Avoidance Motivation (QAAM): Development and Validation.

*This paper presents five studies conducted on 3,644 participants to examine a questionnaire assessing stable individual differences in approach and avoidance motivation. In Study 1, we developed a gender-invariant measure of a multidimensional model of approach and avoidance motivation. In Study 2, we confirmed the factor structure and gender-invariant solution of the instrument and established its relationship with the Big Five Inventory 2 (BFI-2). In Study 3, we provided evidence of the convergent and divergent validity of the new questionnaire by comparing it with several established measures of approach and avoidance motivation. In Study 4, we demonstrated the incremental validity of the QAAM Anxiety scale over BFI Neuroticism and the Behavioral Inhibition System scale from the BIS/BAS Scales in predicting stress-related psychophysiological responses. In Study 5, the questionnaire was shown to be useful in predicting behavioral outcomes in an overearning experimental paradigm. Overall, the new instrument possesses adequate psychometric properties. With its theoretical framework based on a multidimensional model of approach and avoidance motivation, it has the potential to facilitate more experimental studies on the underlying processes of personality traits.*