Embodiments of a modular prosthetic socket for a residual limb of a lower extremity of a patient are provided. Modular components include a base, multiple strut connectors, and multiple longitudinal struts. The base is selected from a collection of bases. The multiple strut connectors are selected from a collection of strut connectors, each strut connector being adjustably connectable to the base along the periphery of the base. The multiple longitudinal struts are selected from a collection of struts, each strut including a thermoplastic-fiber composite material, each strut being connectable to the base along the base periphery via one of the strut connectors. At least one of the component collections includes at least one of multiple sizes or multiple shapes of bases, struts or strut connectors, respectively. The prosthetic socket circumscribes a proximally-open internal space configured to conform to the residual limb of the patient.