Aim: To investigate the influence of gold nanoparticle geometry on the biochemical response of Calu-3 epithelial cells. Materials & methods: Spherical, triangular and hexagonal gold nanoparticles (GNPs) were used. The GNP-cell interaction was assessed via atomic absorption spectroscopy (AAS) and transmission electron microscopy (TEM). The biochemical impact of GNPs was determined over 72 h at (0.0001–1 mg/ml). Results: At 1 mg/ml, hexagonal GNPs reduced Calu-3 viability below 60%, showed increased reactive oxygen species production and higher expression of proapoptotic markers. A cell mass burden of 1:2:12 as well as number of GNPs per cell (2:1:3) was observed for spherical:triangular:hexagonal GNPs. Conclusion: These findings do not suggest a direct shape-toxicity effect. However, do highlight the contribution of shape towards the GNP-cell interaction which impacts upon their intracellular number, mass and volume dose.