The last decade witnessed a vast advancement in several fields of science and technology, including 3D printing. 3D printing is utilized in a wide range of applications, from printing small objects to full-size houses. This research aims to examine thermal neutron attenuation using Acrylonitrile Butadiene Styrene (ABS) filament infused with a thermal neutron absorbent, employing a Monte Carlo simulation toolkit. Several thermal neutron absorbers were tested individually (gadolinium, boron, gold, and cadmium). The simulation results showed a two-centimeter-thick slab infused with boron reduced the total relative dose to one half. Thus, this sample has the potential to be an excellent thermal neutron shielding material. A four-centimeter-thick slab infused with boron registered a neutron relative dose reduction like that of water, which makes the sample a good candidate for water equivalent phantom manufacturing. As for the gadolinium-infused slab, the results indicate that it could be used as a detector cover to discriminate against neutrons in a mixed radiation field. Infusing the ABS slab with gold reduced gamma-ray dose to around 40% of the total relative dose compared to the bare ABS filament. The neutron relative dose remained unchanged for the gold-infused ABS filament. The use of ABS slab infused with cadmium resulted in a steady reduction of the neutron relative dose compared to the bare ABS filament, while the gamma-ray dose remained unchanged. The results for the ABS slab infused with gold and cadmium indicate that these filaments can be used for radiation detection purposes in a mixed neutron-gamma field.