  We formulate a deformation of Rozansky-Witten theory analogous to the
$\Omega$-deformation. It is applicable when the target space $X$ is
hyperk\"ahler and the spacetime is of the form $\mathbb{R} \times \Sigma$, with
$\Sigma$ being a Riemann surface. In the case that $\Sigma$ is a disk, the
$\Omega$-deformed Rozansky-Witten theory quantizes a symplectic submanifold of
$X$, thereby providing a new perspective on quantization. As applications, we
elucidate two phenomena in four-dimensional gauge theory from this point of
view. One is a correspondence between the $\Omega$-deformation and quantization
of integrable systems. The other concerns supersymmetric loop operators and
quantization of the algebra of holomorphic functions on a hyperk\"ahler
manifold.
