It is becoming evident that microRNAs operate within regulatory networks, involving both cooperative actions of multiple microRNAs as well as the targeting by individual microRNAs of multiple components within regulatory pathways and networks. Investigations of the role of the miR-200 family of microRNAs in controlling epithelial to mesenchymal transition (EMT), which has major influence on the propensity of cancer cells to invade, to metastasise, and to resist cancer therapies, have highlighted the importance of microRNA interactions within regulatory networks. The miR-200 family restricts the expression of numerous proteins that otherwise promote the ability of cancer cells to detach and invade. This includes EMT-regulating transcription factors as well as members of the regulatory network that allows dynamic reorganisation of the actin cytoskeleton. We have also found that miR-200 controls expression of an RNA-binding protein, QKI, which is responsible for regulating many alternative splicing events during EMT, including multiple components of the actin cytoskeleton-regulating network, and numerous circular RNAs.