We develop exceptional field theory for E8(8), defined on a (3+248)-dimensional generalized spacetime with extended coordinates in the adjoint representation of E8(8). The fields transform under E8(8) generalized diffeomorphisms and are subject to covariant section constraints. The bosonic fields include an “internal” dreibein and an E8(8)-valued “zweihundertachtundvierzigbein” (248-bein). Crucially, the theory also features gauge vectors for the E8(8) E bracket governing the generalized diffeomorphism algebra and covariantly constrained gauge vectors for a separate but constrained E8(8) gauge symmetry. The complete bosonic theory, with a novel Chern-Simons term for the gauge vectors, is uniquely determined by gauge invariance under internal and external generalized diffeomorphisms. The theory consistently comprises components of the dual graviton encoded in the 248-bein. Upon picking particular solutions of the constraints the theory reduces to D=11 or type IIB supergravity, for which the dual graviton becomes pure gauge. This resolves the dual graviton problem, as we discuss in detail.