Cancer remains one of the leading causes of death worldwide, thereby presenting an urgent need for reliable biomarkers and specific therapeutic targets. Despite the advancements in treatment strategies like radiotherapy, its effectiveness varies depending on the resistance or sensitivity of the cancer type. Thus, understanding the molecular interactions therein is vital for increasing the efficacy of radiotherapy. MicroRNAs (miRNAs) are central to the regulation of oncogenes and tumor suppressor genes, making them significant in the context of cancer. miRNAs are small, endogenous RNAs that serve to modulate gene expression. Recent research has highlighted the role of miRNAs in cancer as key regulators of radiation response. They serve a dual role as contributors to radiosensitizers and radioresistance, as per the cancer type and specific miRNA involved. Studies have also emphasized the function of miRNAs as a predictive biomarker in incident radiation or infrared exposure. This chapter explains how miRNAs function in the systems that control radiation sensitivity. Further investigation into miRNAs and their modulation could lead to more personalized and effective radiotherapy strategies. By analyzing these factors, this chapter seeks to provide a better understanding of how the role of miRNAs in cancer could transform the radiation treatment methods for the same.