  We study the dualities for sigma models with fermions and bosons. We found
that the generalization of the SO(m,m) duality for D=2 sigma models and the
Sp(2n) duality for D=4 sigma models is the orthosymplectic duality OSp(m,m|2
n). We study the implications of this and we derive the most general D=2 sigma
model, coupled to fermionic and bosonic one-forms, with such dualities. To
achieve this we generalize Gaillard-Zumino analysis to orthosymplectic
dualities, which requires to define embedding of the superisometry group of the
target space into the duality group. We finally discuss the recently proposed
fermionic dualities as a by-product of our construction.
