Plastic deformation by dislocation glide is known to be associated with the spontaneous formation of mesoscopic patterns of various types, e.g. cellular dislocation structures during unidirectional deformation and quasi-periodic persistent slip band structures during cyclic deformation. hile it is recognized that dislocation patterning represents a dissipative far-from-equilibrium process, theoretical modelling of those phenomena is complicated by the long-range nature of dislocation interactions inducing collective dislocation behaviour on a mesoscopic scale. n this paper the problem is addressed using a stochastic approach with random uctuations acting on the evolution of the dislocation ensemble. he intensity of the uctuations is determined self-consistently from dynamic dislocation interactions and, hence, re ects correlated dislocation motion. t is shown that those uctuations may induce dislocation patterns by stabilizing non-uniform dislocation distributions. icrostructure-based models are presented for unidirectional and cyclic plastic deformation. n the rst case fractal dislocations distributions corresponding to hierarchically organized dislocation cell structures are obtained, while in the latter case a decomposition into dislocation-rich walls or veins and depleted channels is found, which are associated with the formation of persistent slip bands and matrix structures. he good agreement with experimental observations in single-crystalline f.c.c. metals points at the importance of collective dislocation e ects in the self-organization of those structures.