  We construct $\mathcal{N}=1$ supersymmetric nonlocal theories in four
dimension. We discuss higher derivative extensions of chiral and vector
superfields, and write down generic forms of K\"ahler potential and
superpotential up to quadratic order. We derive the condition in which an
auxiliary field remains non-dynamical, and the dynamical scalars and fermions
are free from the ghost degrees of freedom. We also investigate the nonlocal
effects on the supersymmetry breaking and find that supertrace (mass) formula
is significantly modified even at the tree level.
