Human and animal lives are significantly influenced by the kingdom of plants. The second most common cause of cancer-related fatalities in women is breast cancer. It is still difficult to prevent breast cancer worldwide since it is a multi-step process that involves several cell types. With the existing treatments, advanced breast cancer with distant organ metastases is deemed incurable. Green-synthesized nanoparticles appear to be a new tool for medication delivery in tumour cells and predictive biomarkers for cancer diagnosis. Small size active and passive targeting, the capacity to connect multiple targeting moieties, controlled release, and site-specific targeting are only a few of the special features that nanotechnology offers. This chapter emphasizes the emerging significance of underutilized plant groups, specifically pteridophytes, in the green synthesis of metal-based nanoparticles and their application in breast cancer treatment. Through methods including the unique characteristics of nanoparticles themselves as well as the antioxidative and anticancer qualities present in plants, they can either cause damage to tumour cells or protect healthy cells. Therefore, to maintain healthy cells, underutilized medicinal plants should be further investigated in the field of nano-pharmacology to strengthen their particular targeting of the malignant cells.