Nano zero-valent iron (nZVI) has become one of the most widely studied and applied materials for the treatment of a wide range of contaminants in water and soil over the years. Concurrently, micro- and nanoplastics (MNPs) are considered among the top emerging pollutants detected in all environmental compartments. Understanding the interactions between these materials is crucial given the significant interest in nZVI for environmental remediation and the increasing MNP abundance. This article reviewed current literature focusing on the impact of MNPs on contaminant removal by nZVI in water and soil matrices. Most of the studies suggest that MNPs can inhibit the contaminant removal efficiency through mechanisms such as aggregation, blockage of reactive sites, and premature aging. Critically, modification approaches showed promise: Sulfidated nZVI (S-nZVI) was significantly resistant to MNP detrimental effects compared to pristine nZVI and could offset inhibition caused by MNPs to achieve higher contaminant removal. Several factors affecting the interaction between MNPs and nZVI were critically reviewed, including the type and properties of MNPs (e.g., polymer type and surface charge), the type of nZVI (e.g., sulfidated and modified nZVI), and environmental conditions (e.g., pH, ionic strength, dissolved oxygen, and organic matter). It was concluded that further efforts are needed to improve the performance of nZVI-based remediation technologies in the presence of MNPs.