Although in general the Theory of Planned Behaviour (TPB) has received significant empirical support, there are still some areas in which additional knowledge is needed. In particular, the strength of the influence exerted by the motivational antecedents of intention (personal attitude, subjective norm and perceived behavioural control) is somewhat controversial. In this regard, we argue that the original TPB fails to capture the effect of social factors on the entrepreneurial-intention cognitive process. In this chapter, we discuss the influence of individual and cultural values in the TPB, as social factors that condition the formation of entrepreneurial intentions. We argue that these specific social effects act through two mechanisms. First, they act indirectly, through the antecedents of intentions, by affecting the constructs’ self-reported levels. Secondly, they also moderate the direct effects of these antecedents on intentions. We also argue that the current operationalization of the subjective norms construct limits the model’s ability to capture the social effects involved in this type of cognitive process. This chapter provides a theoretical basis for future empirical research and contributes to a more comprehensive perspective on how entrepreneurial intentions are formed and how they are conditioned by social factors.