  We apply the MIT bag model to study the Boer-Mulders function of the pion, a
$T$-odd function that describes the transverse polarization distribution of the
quark inside the pion. We simulate the effect of the gauge link through the
"one-gluon-exchange" approximation. We consider both the quark helicity nonflip
and double-flip contributions. The result in the MIT bag model is compared with
those in the spectator models.
