Abstract: Macrophages are highly versatile and plastic immune cells that are localized in nearly all organs of the body and contribute to a plethora of physiological and pathological processes in situ. Beside their roles as major players in the “first line of defense” under inflammatory conditions, macrophages are known to participate in tissue homeostasis maintenance. Therefore, these cells are capable of removing cell debris and secreting cytokines and growth factors influencing cells in their local microenvironment and vice versa. The eye, which represents one of the most sophisticated organs in the body of vertebrates, harbors multiple macrophage populations that are localized in and adapted to different compartments. Microglia, the resident immune cells of the central nervous system (CNS) including the retina, are mainly restricted to the retina itself and the optic nerve, whereas the cornea, ciliary body and choroid contain different myeloid cell types with distinct tasks to fulfill. In comparison to brain microglia (bMG) or other CNS-associated macrophages (CAMs), that were extensively studied in mice and humans (Goldmann et al., 2016; Masuda et al., 2019), ocular macrophages (oMacs) are far less understood in points of their exact origin, fate and heterogeneity. To address this issue, recent studies applied state-of-the-art fate mapping approaches to identify the exact embryonic origin of the oMacs and single-cell transcriptomics to dissect the myeloid landscape in multiple eye compartments under homeostatic and pathological conditions (O’Koren et al., 2019; Wieghofer et al., 2021). Here, we would like to recapitulate the most important developments in fate mapping and single-cell analysis leading to these findings and delineate emerging technologies that may further fuel the research in myeloid cell biology in the brain and eye.