Multiple sclerosis, and its animal model experimental autoimmune encephalomyelitis, are neuroinflammatory diseases driven by autoreactive pathogenic TH cells which elicit demyelination and axonal damage. How TH cells acquire pathogenicity and communicate with myeloid cells and cells of the central nervous system remain unclear. IL-1β is recognized to play an important role in EAE and perhaps MS. Clinical EAE is significantly attenuated in IL-1 receptor-deficient and IL-1β-deficient mice, and IL-1β is found in the blood, cerebrospinal fluid, and CNS lesions of MS patients. Here, we will focus on new reports which elucidate the cellular sources of IL-1β and its actions during EAE, in both lymphoid tissues and within the CNS. Several immune cell types serve as critical producers of IL-1β during EAE, with the cytokine inducing responses in hematopoietic and non-hematopoietic cells. These findings from the EAE model should inspire efforts towards investigating the therapeutic potential of IL-1 blockade in MS.