Glioblastoma is the most common and aggressive primary brain tumour. Cancer hijacks developmental pathways and several studies have identified a stem cell-like population in glioblastoma following neurodevelopmental trajectories. In the foetal neocortex, a type of neural stem cell called basal progenitor is thought to be responsible for neocortical expansion. Basal progenitors exist in different morphotypes, and greater morphological complexity underlies their increased proliferation. We thus propose that cell morphology also plays a role in the proliferation of glioblastoma stem cells. Through immunostaining of patient samples, we show that glioblastoma stem cells have a vast morphological heterogeneity in human glioblastoma tissue and their morphology resembles neural progenitors in the developing neocortex. The morpho-types observed are conserved in glioblastoma stem cells cultured in 2D as well as in patient derived organoids. To then understand the function of cell morphology in tumour progression, we genetically manipulate morpho-regulatory molecules in glioblastoma stem cells and show that those morpho-regulatory molecules which control the proliferation of basal progenitors also affect the proliferation of glioblastoma stem cells, as well as the formation of tumour cell-tumour cell connections. Overall, glioblastoma stem cells display extensive morphological heterogeneity, like basal progenitors in the developing neocortex. Morpho-regulatory molecules do not only control cell shape but contribute to the proliferation and cell-cell connection of glioblastoma stem cells. We envision that the identification of novel morpho-regulatory molecules controlling tumour progression will open new therapeutic windows through pharmacological targeting and drug repurposing.