The microcirculation, comprising arterioles, capillaries, and venules, is critical for tissue perfusion and oxygen delivery. The endothelial glycocalyx, which lines the luminal surface of the microvascular endothelium (the largest interface in the circulatory system), plays a pivotal role in vascular homeostasis and microcirculatory integrity. This chapter/review is structured into five sections: Section “Structure of Glycocalyx” describes the core structure of the glycocalyx, composed of membrane-bound proteoglycans, glycosaminoglycans, glycoproteins, and adsorbed plasma proteins, which forms the functional basis of glycocalyx. Section “Patho-Physiological Actions of Glycocalyx” outlines key physiological functions of glycocalyx, including, but not limited to, mechanosensing and transduction for the activation of endothelial nitric oxide synthase, regulation of vascular permeability, modulation of leukocyte trafficking and receptor accessibility, and protection against inflammatory mediators. Based on these functions, the section also reviews corresponding alterations observed under pathological conditions. Sections “The Causal Link and Self-Perpetuating Vicious Cycle Between Glycocalyx Degradation and Microcirculatory Dysfunction” and “General Mechanisms for Endothelial Glycocalyx Degradation in Endotoxemia/Sepsis” explore the mechanisms of glycocalyx degradation during inflammation, addressing its bidirectional (casual and reciprocal) relationship with microcirculatory dysfunction (section “The Causal Link and Self-Perpetuating Vicious Cycle Between Glycocalyx Degradation and Microcirculatory Dysfunction”), and roles of enzymic mediators: heparinase, hyaluronidase, and matrix metalloproteinases in endotoxemia-induced glycocalyx shedding (section “General Mechanisms for Endothelial Glycocalyx Degradation in Endotoxemia/Sepsis”). Section “Therapeutic Strategies for Glycocalyx Rearrangement” reviews therapeutic strategies aimed to prevent and/or attenuate glycocalyx degradation (section “Prevention or Attenuation of Glycocalyx Degradation”) and promote its regeneration (section “Promoting Restoration and Managing Reconstitution of Degraded Glycocalyx”). Section “Sexually Dimorphic Phenomenon of Endothelial Glycocalyx” discusses emerging evidence of sex-specific phenotype in regulating glycocalyx, with underlying mechanisms yet to be fully defined.