Aim: This research aims to assess the cytotoxicity of Triplex Hot, Trevalon H, and dental products of India (DPI) heat cure acrylic resins by comparing their optical density at 1, 24, and 72 hours and evaluating the residual monomer's effect on fibroblast cells. Materials and methods: A total of 90 heat-cured acrylic resin specimens (30 each of Trevalon H, Triplex Hot, and DPI) were divided into three groups. HT-1080 fibroblasts were cultured, and resin samples were introduced into respective wells. The inflammatory response was assessed after 1, 24, and 72 hours of incubation. Cell vitality was measured using an 3-(4,5-dimethylthiazol-2-yl)—2,5-diphenyl tetrazolium bromide (MTT) assay and spectrophotometer. Statistical analysis included one-way analysis of variance (ANOVA) and post hoc Tukey's test. Results: All three groups have displayed cytotoxicity at varied levels after 1 hour, 24 hours, and 72 hours, but with no significant difference among groups after 24 hours, increasing safety concerns towards their usage. H3 samples showed a higher level of cytotoxicity in general when compared with H1 and H2. Conclusion: It has been concluded that levels of cytotoxicity were found to be higher and lower after 1 hour and 72 hours incubation period respectively, whereas all the resins displayed similar levels of cytotoxicity after 24 hours explaining that the residual monomers will percolate maximum within the first 24 hours after processing of dentures. Clinical significance: It was discovered that resin had varying degrees of cytotoxic effects, raising concerns about the safe clinical application of these materials. Hence proper care should be taken during the selection of resin materials to prevent adverse effects on operators and patients.