  We study giant graviton expansions of the superconformal index of 4d
orbifold/orientifold theories. In general, a giant graviton expansion is given
as a multiple sum over wrapping numbers. It has been known that the expansion
can be reduced to a simple sum for the ${\cal N}=4$ $U(N)$ SYM by choosing
appropriate expansion variables. We find such a reduction occurs for a few
examples of orbifold and orientifold theories: $\mathbb{Z}_k$ orbifold and
orientifolds with $O3$ and $O7$. We also argue that for a quiver gauge theory
associated with a toric Calabi-Yau $3$-fold the simple-sum expansion works only
if the toric diagram is a triangle, that is, the Calabi-Yau is an orbifold of
$\mathbb{C}^3$.
