Entrepreneurial activity is considered to be an intentionally planned behaviour. Consequently, entrepreneurial intention (EI) may be evaluated via theory of planned behaviour (TPB). According to Ajzen's TPB, EI is explained by three antecedents: attitude towards entrepreneurial behaviour, perceived social norms and perceived behaviour control in other words, self-efficacy. Although this model is widely tested empirically, new research regarding moderation effects may be valuable [1]. Moreover, [2] argues that personal factors such as previous start-up experience are relevant concerning the model. Accordingly, in this study, moderation effect of start-up experience is added in TPB model from a convenience sample of 528 undergraduate business administration students from the three most economically developed cities in Turkey. Hypotheses are tested by means of hierarchical multiple regression analysis. Coefficients are estimated using ordinary least squares. In order to test the moderator effect, significance values of the interaction term is assessed. According to the results, all of the relations within the model are significant. Ajzen's TPB holds for the Turkish case. Moreover, for the students with a past start-up experience, the effect of both self-efficacy and personal attitude towards entrepreneurial behaviour on entrepreneurial intensity increases. This is a promising result for the future studies.