Small interfering RNA (siRNA), with its highly sequence-specific ability to modulate target gene expression, is seen as a promising therapeutic approach in cancer therapy. However, the major impediments to widespread clinical utilization are the optimal and durable targeting of target genes and safe and effective delivery of siRNA to the site of interest in the tumor niche. In this review, we will discuss gold nanocarriers with varied geometries and architecture as siRNA delivery vehicles for targeted cancer treatment. In addition, the gold nanostructures provide optical imaging functionalities as well as the ability to optically track delivery of siRNA to the cancer site, thus enabling true theranostics.