IRAK-M is a negative regulator of Toll-like receptor (TLR) signaling. IRAK-M is induced upon TLR stimulation and prevents the dissociation of IRAK and IRAK-4 from MyD88, inhibiting the formation of IRAK-TRAF6 complexes. IRAK-M−/− cells exhibit increased cytokine production upon TLR/IL-1 stimulation and bacterial challenge, leading to enhanced inflammatory responses. IRAK-M−/− mice show impaired endotoxin tolerance, a protective mechanism against endotoxin shock. IRAK-M regulates TLR signaling and innate immune homeostasis by inhibiting the dissociation of IRAK and IRAK-4 from the TLR signaling complex, rather than by affecting their recruitment or association with TRAF6. This study highlights the critical role of IRAK-M in maintaining the balance of innate immune responses.IRAK-M is a negative regulator of Toll-like receptor (TLR) signaling. IRAK-M is induced upon TLR stimulation and prevents the dissociation of IRAK and IRAK-4 from MyD88, inhibiting the formation of IRAK-TRAF6 complexes. IRAK-M−/− cells exhibit increased cytokine production upon TLR/IL-1 stimulation and bacterial challenge, leading to enhanced inflammatory responses. IRAK-M−/− mice show impaired endotoxin tolerance, a protective mechanism against endotoxin shock. IRAK-M regulates TLR signaling and innate immune homeostasis by inhibiting the dissociation of IRAK and IRAK-4 from the TLR signaling complex, rather than by affecting their recruitment or association with TRAF6. This study highlights the critical role of IRAK-M in maintaining the balance of innate immune responses.