  Lensing of one member of a binary by its companion is studied for several
classes of binaries. For binaries in which at least one member is an ordinary
(non-compact) star, the optical depths to lensing is extremely low, $\tau\lsim
v_\esc^4/c^4\sim 10^{-11}$. Here $v_\esc$ is the escape velocity from the
component with the weaker potential. Binaries composed of two compact objects
can have higher optical depths. About 0.2\% of millisecond pulsar binaries will
be self-lensing. Such objects can be used to probe the pulsar-emission
mechanism.
