ORIGINAL ARTICLE Background: The evidence suggests nutrition style as a key determinant of health. On the other hand, nutrition literacy is a key determinant of nutrition decisions and behaviors. This study aimed to develop and validate an inventory in order to predict nutrition literacy promoting behavior based on the theory of planned behavior (TPB) in the youth. Methods: In this cross-sectional study, 203 students (100 females and 103 males) were selected using the randomized cluster method from dormitories in Shiraz University of Medical Sciences. They were supposed to complete Nutrition Literacy Promoting Behavior based on TPB (TPB-NLPB) questionnaire. The tool was developed using relevant scientific literature and its validity was confirmed by the experts’ panel (n= 6). The instrument includes four subscales: attitude toward behavior, subjective norm, perceived behavioral control, and behavioral intention. The reliability and validity of the instrument were assessed by exploratory and confirmatory factor analysis and Cronbach’s alpha coefficient. Results: The coefficients of Cronbach’s alpha (α= 0.87), Guttmann method (λ 1= 0.84 to λ 6= 0.91), and convergent validity (0.74) were estimated (P< 0.01). The exploratory factor analysis demonstrated five factors, which clarified 64.91% of the scale’s variance. Second-order confirmatory factor analysis pointed out that the factor was well matched up onto the principal factor. Consequently, the five-factor model was appropriate for the data using fit index techniques for adjusting the scale. Conclusions: The results confirmed the well-adjusted reliability and psychometric properties of the TPB-NLPB and its usefulness for the relevant studies.