  We introduce gauge-invariant quark and gluon angular momentum distributions
after making a generalization of the angular momentum density operators. From
the quark angular momentum distribution, we define the gauge-invariant and
leading-twist quark {\it orbital} angular momentum distribution $L_q(x)$. The
latter can be extracted from data on the polarized and unpolarized quark
distributions and the off-forward distribution $E(x)$ in the forward limit. We
comment upon the evolution equations obeyed by this as well as other orbital
distributions considered in the literature.
