We study the generalization of noncommutative gauge theories to the case of
orthogonal and symplectic groups. We find out that this is possible, since
we are allowed to define orthogonal and symplectic subgroups of noncommuta
tive unitary gauge transformations even though the gauge potentials and gau
ge transformations are not valued in the orthogonal and symplectic subalgeb
ras of the Lie algebra of antihermitean matrices. Our construction relies o
n an anti-automorphism of the basic noncommutative algebra of functions whi
ch generalizes the charge conjugation operator of ordinary field theory. We
show that the corresponding noncommutative picture from low energy string
theory is obtained via orientifold projection in the presence of a non-triv
ial NSNS B field. (C) 2000 Elsevier Science B.V. All rights reserved.