Abstract This work presents a continuum damage analysis of the effect of aligned microcracks on a dominant crack in an otherwise anisotropic medium. This geometry is particularly relevant for composite media with an aligned reinforcement phase, where aligned cracking can change the magnitude and principal axes of anisotropy. Provided that the density of aligned microcracks reaches a stable saturation value near the crack tip, the near-tip stress intensity factor, K I s , may be related to the remote value, K I 0 , in terms of the anisotropic properties of the undamaged and saturated media. Results show that of all types of damage, that which increases compliance in a direction normal to the crack plane typically reduces K I s / K I 0 near the crack tip most significantly, while comparable increases in compliance parallel to the crack growth direction produce a relatively small change. Reduction in K I s K I 0 due to increased shear compliance may be 80% of that due to increased compliance normal to the crack plane. For damage consisting of aligned microcracks, the most effective reduction in K I s / K I 0 occurs when the microcracks are oriented parallel, rather than perpendicular to the main crack. This conclusion holds even for alumina/aluminum and graphite/epoxy systems that display large anisotropy. In those cases, optimal reduction in K I s / K I 0 occurs when in addition to parallel macro and microcracks, the stiffer direction is perpendicular to the crack surfaces. This case corresponds, for example, to macrocrack extension perpendicular to aligned fibers or layers in composite materials, with pinned microcracking through fiber or layer cross sections.