We study the localization of classical waves in weakly scattering two-dimensional systems with anisotropic disorder. The analysis is based on a perturbative path-integral technique combined with a spectral filtering that accounts for the first-order Bragg scattering only. It is shown that in the long-wavelength limit the radiation is always localized, and the localization length is independent of the direction of propagation, the latter in contrast to the predictions based on an anisotropic tight-binding model. For shorter wavelengths that are comparable to the correlation scales of the disorder, the transport properties of disordered media are essentially different in the directions along and across the correlation ellipse. There exists a frequency-dependent critical value of the anisotropy parameter, below which waves are localized at all angles of propagation. Above this critical value, the radiation is localized only within some angular sectors centered at the short axis of the correlation ellipse and is extended in other directions. Anderson-type localization of classical waves in disordered systems is a topic of increasing current interest due to its fundamental role in wave-matter interactions, and also due to the significance of possible applications [1]. While the localization in one-dimensional (1D) random systems has been studied in considerable detail, a quantitative analytical description of the phenomenon in higher dimensions still presents a challenge. The question here concerns the relationship between the localization and its characteristics (say, localization length), on the one hand, and the correlation properties of the scattering potential, on the other. However, most of the existing results are related to a ␦-correlated potential or obtained numerically by using discrete schemes, such as the tight-binding model, and therefore are relevant mainly for low-frequency excitations. Moreover, the theories describing wave localization have been developed primarily for systems with isotropic disorder, and those considering anisotropy [2,3] are not directly applicable to classical waves. The only exception is the limiting case of an infinite correlation scale in one direction (randomly stratified media), which has been studied rather comprehensively [4]. In such media, the radiation is localized in the direction across the layers and is typically channeled along the layers, similar to that occurring in a regular waveguide. Although this model can be useful for understanding the basic mechanisms of wave localization in anisotropic systems, it is of little help when media with finite anisotropy are concerned. Experimental studies dealing with both electronic [5] and classical wave [6,7] transport in anisotropic systems have been initiated only recently and are far from being complete.The present study is based on a path-integral approach [8] that enables a perturbative analysis of the localization length in random media with continuous-type disorder described by an arbitrary correlation function. It is...