G protein ${eta}$-like ($G{eta}L$) is a member of WD repeat-containing family which are involved in various intracellular signaling events. In our previous report, we demonstrated that $G{eta}L$ regulates TNF${alpha}$-stimulated NF-${kappa}$B signaling by interacting with and inhibiting phosphorylation of $I{kappa}B$ kinase. However, $G{eta}L$ itself does not seem to regulate IKK directly, because it contains no functional domains except WD domains. Here, using immunoprecipitation and proteomic analyses, we identified protein phosphatase 4 as a new binding partner of $G{eta}L$. We also found that $G{eta}L$ interacts with PP2A and PP6, other members of the same phosphatase family. By interacting with protein phosphatases, which do not directly bind to IKK${eta}$, $G{eta}L$ mediates the association of phosphatases with IKK${eta}$. Overexpression of protein phosphatases inhibited TNF${kappa}$-induced activation of NF-${kappa}$B signaling, which is an effect similar to that of $G{eta}L$ overexpression. Down-regulation of $G{eta}L$ by small interfering RNA diminished the inhibitory effect of phosphatases, resulting in restoration of NF-${kappa}$B signaling. Thus, we propose that $G{eta}L$ functions as a negative regulator of NF-${kappa}$B signaling by recruiting protein phosphatases to the IKK complex.