We consider the Heun equations in the context of the quasi-exactly-sol
vable spectral problems and establish the conditions for this class of
equations to admit algebraic solutions. The Schrodinger operators tha
t can be associated with Heun equations are constructed explicitly; in
some cases, we present their supersymmetric partners. We study a Heun
-like system of equations which is relevant for the classical solution
of the two-dimensional Abelian-Higgs model.