Bone defects are commonly associated with trauma, congenital disorders, non-unions, and infections following surgical procedures. Defects which are unable to heal spontaneously are categorized as “critical sized” and are treated using bone grafts to facilitate the bone regeneration and/or stabilization. Grafting materials can be natural or synthetic, each having their respective advantages and disadvantages. Synthetic bone grafts are favored due to their ability to be tailored to exhibit desired properties and geometric configurations. β-tricalcium phosphate (β-TCP), a synthetic grafting material, has been widely utilized for regenerative purposes due to its osteoconductive properties. In combination with 3D printing, grafts can be further customized with respect to their macro and micro features. One way to customize devices using 3D printing is by varying the surface area, by varying the internal component measurements. The objective of this study was to compare the effect of variations on the porosity and surface area of 3D printed β-TCP scaffolds with different strut diameters and the effect on cell proliferation in vitro. ß-TCP scaffolds were printed using a custom-built 3D direct-write micro printer with syringes equipped with different extrusion tips (f_diameter: 200 µm, 250 µm and 330 µm). After sintering and post processing, scaffolds were subjected to micro-computed tomography (µCT) and a Scanning Electron Microscope (SEM) to evaluate surface area and porosity respectively. Compressive strength was assessed using a universal testing machine. Cell proliferation was assessed through cellular viability, using human osteoprogenitor cells. The surface area of the scaffolds was found to increase with the smaller strut diameters. Statistically significant differences (p<0.05) were detected for cellular proliferation, between the smallest extrusion diameter, 200 μm, and the largest diameter, 330 μm, after 48-, 72-, and 168-hours. No statistical significances were detected (p>0.05) with regards to the mechanical properties between groups. This study demonstrated that a smaller diameter rod yielded a higher surface area resulting in increased levels of cellular proliferation. Therefore, tailoring rod dimensions has the capacity to enhance cellular adhesion and ultimately, proliferation.