Gold nanoparticles (GNPs) possess a number of useful characteristics that have catapulted them into the mainstream of cancer research. Their optical properties enable them to be used in photodynamic and photothermal therapy as well as contrast agents in photoacoustic imaging. In addition, the ability to bind ligands to the GNP surface has made them valuable bio-markeraware drug carriers. But the effectiveness of any cancer fighting tool relies on homogenous distribution and penetration throughout the tumor, and the uptake and transport dynamics of GNPs has previously been held to monolayer cell models. In this work, multicellular layers (MCLs) are used as a solid tumor model to measure the penetration and uptake of GNPs in tumor tissue. MCLs offer a unique way to bridge the gap between in vitro single-layer cell models and the in vivo tumor. The effects of increased cell-to-cell connections, extracellular matrix and tumor characteristics are investigated to deliver new insights into the transport of GNPs in tissue.