3D printing has been shown to be a robust and inexpensive manufacturing tool for a range of applications within biomedical science. Here we report the design and fabrication of a 3D printer-enabled microfluidic device used to generate cell-laden hydrogel microspheres of tunable sizes. An inverse mold was printed using a 3D printer, and replica molding was used to fabricate a PDMS microfluidic device. Intersecting channel geometry was used to generate perfluorodecalin oil-coated gelatin methacrylate (GelMA) microspheres of varying sizes (35–250 μm diameters). Process parameters such as viscosity profile and UV cross-linking times were determined for a range of GelMA concentrations (7–15% w/v). Empirical relationships between flow rates of GelMA and oil phases, microspheres size, and associated swelling properties were determined. For cell experiments, GelMA was mixed with human osteosarcoma Saos-2 cells, to generate cell-laden GelMA microspheres with high long-term viability. This simple, inexpensive method does not require the use of traditional cleanroom facilities and when combined with the appropriate flow setup is robust enough to yield tunable cell-laden hydrogel microspheres for potential tissue engineering applications.