There is a significant unmet need for the development of complex and scalable 3D colorectal cancer (CRC) models. Presently, there is no known method for predicting patient-response to chemotherapy, and many nonresponding patients undergo this treatment which has no therapeutic value and significant negative impacts on health and wellbeing. It has been recently demonstrated that patient-specific microtumours, known as tumour spheroids, can be cultured in vitro from patient biopsy's and are predictive of chemotherapy-response in CRC. However, current approaches are low throughput and cannot be readily scaled to address the large clinical need. Bioprinting, the controlled 3D patterning of cell-laden biocompatible materials known as 'bioinks', has untapped potential to reproduce the CRC tumour spheroid model in a robust, high throughput manner. At this time, no scalable bioprinted CRC tumour spheroid model has been reported in the literature. Consequently, this thesis addresses this space, outlining the development of a high throughput bioprinting assay for CRC tumour spheroid chemotherapy-response. In Chapter 3, a bioink was formulated which ubiquitously supports spontaneous spheroid self-assembly in every tested CRC line. In Chapter 4, the characteristics of these tumour spheroids are explored, and found to exhibit important characteristic features of tumours in vivo, such as zonal hypoxia and necrosis. Finally, in Chapter 5, work from the previous two chapters is used to develop a high throughput, bioprinted chemotherapy and radiotherapy-response assay, using non-invasive high content microscopy to measure the growth of spheroids challenged by therapy. Here, the throughput and utility of the system is validated through the accurate measurement of many thousands of tumour spheroids simultaneously, paving the way for future use of scalable bioprinted CRC spheroid assays as a clinical tool.