Autophagy is a conserved cellular clearance pathway that supports homeostasis by removing damaged or superfluous intracellular components. Within microglia, autophagy is emerging as a regulator of key processes that modify neurodegeneration, including phagocytosis, cytokine secretion, and senescence. Many studies that have examined the effect of disrupted autophagy on microglial functions have used genetic knockouts of the machinery required to conjugate microtubule-associated light chain 3 (LC3) to the autophagic membrane. However, much of this molecular machinery is also required for a set of distinct but related pathways known as the conjugation of ATG8s to single membranes (CASM). CASM includes processes of particular importance in microglia, such as LC3-associated phagocytosis and LC3-associated endocytosis. It is thus not clear which of the effects of the disruption of LC3 conjugation in microglia are attributable to the loss of autophagy or the loss of CASM function. In this review, we describe the mechanisms of autophagy and CASM and highlight the effects of the loss of these pathways on key microglial processes relevant to brain ageing and neurodegenerative diseases. We discuss recent literature that has revealed the effects of ageing and neurodegeneration on microglial autophagy, and the effects of microglial autophagy and/or CASM disruption on key microglial functions such as phagocytosis, cytokine secretion, and senescence. Finally, we discuss the potential therapeutic implications of these findings for neurodegeneration and highlight key unanswered questions for future research.