The homeodomain transcription factor Pitx2 has been conventionally studied during embryonic development where it governs the evolutionarily conserved left-right (LR) body plan and directs asymmetric organ morphogenesis. Specifically, Pitx2 directs the embryonic folding and looping of the intestine, as well as the formation and organization of its vasculature and associated smooth muscle, crucial for postnatal intestinal nutrient absorption. However, it is still unknown whether Pitx2 plays a continuous role in the postnatal intestine, as reduced Pitx2 expression during embryogenesis causes developmental defects that affect the absorptive function of the postnatal intestine. Thus, my dissertation investigates whether Pitx2 plays a function in the postnatal intestine beyond embryogenesis. This is especially relevant as recent data suggest that Pitx2 is one of the most highly downregulated genes in patients with Inflammatory Bowel Disease (IBD) and appendicitis, indicating an important role for Pitx2 in intestinal health and disease. By deleting Pitx2 in neonates, I show that Pitx2 is necessary for the proper postnatal maturation of the neonatal mouse intestine, specifically by regulating the maturation of villi and crypts, and the self-renewal and proliferation of progenitor epithelial cells. By deleting Pitx2 in the mature intestine, I show that Pitx2 directs the proliferation and differentiation of Intestinal Stem Cells (ISCs) through two main ways: 1) directly in ISCs to affect their expansion and self-renewal, 2) via non-cell autonomous signaling originating from secretory enteroendocrine cells (EECs) and tuft cells. Of note, Pitx2 inducible knockout mice (iKO) have significantly increased number of secretory tuft, Paneth, and goblet cells at the expense of absorptive enterocytes. Ultimately, loss of Pitx2 in neonates or adult mice leads to failure to gain weight and severe sickness, demonstrating that Pitx2 is necessary for postnatal intestinal development and function. Moreover, I provide new insights into the genetic mechanisms involved in postnatal intestinal maturation and show that this transition is required to support the change in diet upon weaning. My data emphasize the vital role of Pitx2 in maintaining intestinal function, specifically through its involvement in the formation of the ISC niche and ISC differentiation. Further, my work underscores the significance of Pitx2 in the postnatal intestine, in addition to its well-established role during embryogenesis. In summary, my results highlight the complex and dynamic Pitx2-dependent genetic regulation during intestinal maturation, homeostasis and absorptive function.