The orientation of anisotropic solid particles suspended in thermoplastics is examined by wide angle x‐ray diffraction (WAXD). The state of orientation is assessed as a function of the deformation or processing history of a filled material. The technique is based onaprioriassessing the relationship of the position of crystallographic planes in the anisotropic particles. Our study uses mica, talc, and DuPont Kevlar fibers in which the orientations of crystallographic planes are well established. WAXD pole figures have been obtained for systems with varying processing histories. The results are represented in terms of orientation factors of the type which have been developed to represent polymer chain and crystallographic orientation in fibers and films. Specific application is made to: (i) filament extrusion, (ii) melt spinning, (iii) sheet extrusion, (iv) compression molding, (v) cold rolling, and (vi) injection molding. The differences in orientation development of suspended fibers and flakes in these various processing operations are described. Generally fibers orient in the direction of flow and flakes orient with their normals perpendicular to surfaces in extrudates and molded products.