<p>Fiber-reinforced thermoplastic lattice structures produced by fused deposition modeling (FDM) offer a promising route to lightweight, load-tailored components for rapid tooling, yet rational topology selection remains hindered by the lack of systematic structure-property data. This study addresses this gap by characterizing the compressive behavior of FDM-printed carbon-fiber-reinforced polyamide 6 (PA6-CF) lattice structures across three infill patterns (Cross Hatch, Gyroid, 3D Honeycomb), three relative densities (10%, 20%, 30%), three strain rates (6.6 × 10⁻³ to 4 × 10⁻¹ s⁻¹), and two loading orientations. Gibson-Ashby scaling analysis reveals that the dominant deformation mechanism — and therefore the design-relevant scaling law — depends critically on topology: Cross Hatch follows linear strength scaling (<i>n</i> ≈ 1.0) governed by strut buckling, while Gyroid and 3D Honeycomb exhibit super-quadratic scaling (<i>n</i> = 2.72 and 3.03, respectively), reflecting a buckling-to-yielding transition at higher densities that enables disproportionate strength gains. Mechanical anisotropy is topology-dependent: Cross Hatch suffers a 68% property reduction under transverse loading due to geometric directionality and unfavorable fiber alignment, whereas Gyroid maintains near-isotropic response (anisotropy indices 1.0–1.9) by distributing loads across multiple fiber orientations. Strain rate sensitivity is negligible for stretch-dominated Cross Hatch but increases strength by 10–25% for Gyroid and Honeycomb at higher densities, an advantage for impact applications. These findings establish topology- and density-specific design criteria that allow engineers to select PA6-CF lattice configurations based on loading mode, directionality, and energy absorption requirements, replacing empirical trial-and-error with quantitative performance predictions for rapid tooling applications.</p>