The importance of Small and Medium-sized Enterprises (SMEs) to the growth of economies cannot be overemphasized, as they are considered key contributors to economic development. They can identify and seize opportunities to provide solutions to societal problems. The conventional marketing mix (4Ps) has been the dominant traditional framework that has greatly facilitated marketing development in theory and practice. However, in literature, some scholars posit that the 4Ps are oriented to the internal aspects of SMEs, leaving out the external, which includes the customer. In general, the marketing mix ignores the evolving nature of the consumer, whose focus is on the attainment of value, better interaction, and trust, all of which are the foundations of relationship marketing. This chapter begins by providing a comprehensive overview of how SMEs understand and relate to their customers. This is followed by the antecedents of the 4Ps variables and how they have been applied by SMEs. The chapter will then progress with literature related to customer relationship management and its relevance in the fourth industrial revolution in the realm of SMEs, referring to the 4Cs of marketing.