We study the structure of graded Leibniz algebras with arbitrary dimension and over an arbitrary base field K. We show that any of such algebras £ with a symmetric G-support is of the form £ = U-∑jIj with U a subspace of £1, the homogeneous component associated to the unit element 1 in G, and any Ij a well described graded ideal of £, satisfying [Ij, Ik]= 0 if j≠ k. In the case of £ being of maximal length, we characterize the gr-simplicity of the algebra in terms of connections in the support of the grading.