AbstractFused filament fabrication (FFF) is an increasingly popular three‐dimensional (3D) printing technology known for its ability to produce complex 3D models at a low‐cost using polymer materials. Despite its advantages, the poor surface finish and high layer resolution in FFF‐printed parts have hindered its wider adoption, particularly for applications requiring high transparency. Thus, the current study investigates the transparency evaluation of chemically post‐processed 3D‐printed transparent polylactic acid (PLA) parts, focusing on enhancing optical transparency. Fused Filament Fabrication was employed to produce transparent parts made from PLA filament, which were subsequently treated at various time settings using various solvents, including tetrahydrofuran (THF), chloroform or trichloromethane (TCM), and ethyl acetate (EA). This study examines the impact of chemical post‐processing on the surface roughness, transparency, mechanical properties, and dimensional accuracy of solvent treated parts. It has been found that the THF solvent with 40 s of immersion time resulted in a maximum transmittance of 74.66% and minimum surface roughness of 1.777 μm. Based on this finding a case study was also conducted to apply the findings of the current investigation to a practical application. The findings highlight the potential of chemical‐based post‐processing techniques to improve the optical properties of 3D printed PLA, offering a promising approach for applications in optics, medical devices, and consumer goods requiring transparent components.Highlights Effect of chemical post‐processing on 3D‐printed PLA parts was investigated. Tetrahydrofuran, chloroform, and ethyl acetate were used as solvents. Surface roughness, transparency, hardness, and dimensional accuracy were analyzed. Reported a maximum transmittance of 74.66% and minimum surface roughness of 1.777 μm.