  In this paper we study an eigenvalue problem for the so called
$(p,2)$-Laplace operator on a smooth bounded domain under a nonlinear Steklov
type boundary condition, namely \begin{equation} \left\{ \begin{aligned}
-\Delta_pu-\Delta u & =\lambda a(x)u \ \ \text{in}\ \Omega,\\ (|\nabla
u|^{p-2}+1)\dfrac{\partial u}{\partial\nu} & =\lambda b(x)u \ \ \text{on}\
\partial\Omega . \end{aligned} \right. \end{equation} Under suitable
integrability and boundedness assumptions on the positive weight functions $a$
and $b$, we show that, for all $p>1$, the eigenvalue set consists of an
isolated null eigenvalue plus a continuous family of eigenvalues located away
from zero.
