3D printing is a fast and simple method for creating and refining objects from representations based on computer-aided design files. Recent improvements in accessibility, affordability, and capabilities of 3D printing technologies have resulted in several successful applications of such techniques in electrochemistry and sensing research. One particular example that has garnered a great deal of interest is 3D-printed flow cells. These devices can enable more efficient design and implementation of flow-through laboratory devices with channel dimensions of tens to hundreds of micrometers or more by eliminating barriers, such as geometrical restrictions, equipment needs, and technical expertise that are associated with other methods used for producing fluidic devices. Electrochemical and electrochemiluminescence sensing capabilities can be introduced into these flow-cells by incorporating design elements that enable the integration of electrodes and optical components. Here, we demonstrate the production and application of flow-through electrochemical sensors based on 3D-printed flow cells prepared using a digital light processing projector-based 3D printer.