Disclosed herein are static mixer assemblies, and related methods of fabrication and use. The disclosure provides advantageous static mixer assemblies, and improved systems/methods for utilizing and/or fabricating the static mixer assemblies. The disclosure provides static mixer assemblies fabricated at least in part by additive manufacturing (e.g., via a 3D printing process, such as, for example, via a fused deposition modeling (“FDM”) process), and related methods of use. The static mixer assemblies of the present disclosure can be particularly well-suited for applications such as, without limitation, high performance liquid chromatography (“HPLC”) applications. The additive manufacturing or 3D printing processes (e.g., FDM or LAMT techniques) as described herein can be used to manufacture static mixer assemblies with complex shapes/designs (e.g., and that are highly effective yet small in shape).