This study presents the first efficient photoinduced miniemulsion ATRP (atom transfer radical polymerization) using red or near-infrared (NIR) light. The process utilizes methylene blue (MB⁺) as a water-soluble photocatalyst, which is efficiently excited by red/NIR light to initiate and mediate the polymerization. The MB⁺ reduces the ATRP deactivator in the presence of water-soluble electron donors, enabling controlled polymerization with low dispersity (1.09 ≤ D ≤ 1.29) and high conversion within one hour. The study highlights the advantages of longer-wavelength light, particularly NIR, for large-scale polymerization in dispersed media due to its superior penetration. The mechanism involves the reduction of the ATRP deactivator at the water/organic interface, generating an activator that initiates polymerization and controls radical propagation through a reversible redox equilibrium between Cu(I) and Cu(II) complexes. The use of MB⁺ as a photocatalyst offers excellent oxygen tolerance and precise control, eliminating the need for rigorous deoxygenation. The polymerization was successfully demonstrated in various reactor sizes, with NIR light showing superior performance even in larger reactors. The results demonstrate the potential of NIR-driven miniemulsion ATRP for rapid, controlled, and oxygen-tolerant polymerization in dispersed media, offering a greener and more practical approach for industrial applications. The method allows for varying degrees of polymerization with high control and enables temporal control of the polymerization process, making it a valuable contribution to the field of emulsion polymerization.This study presents the first efficient photoinduced miniemulsion ATRP (atom transfer radical polymerization) using red or near-infrared (NIR) light. The process utilizes methylene blue (MB⁺) as a water-soluble photocatalyst, which is efficiently excited by red/NIR light to initiate and mediate the polymerization. The MB⁺ reduces the ATRP deactivator in the presence of water-soluble electron donors, enabling controlled polymerization with low dispersity (1.09 ≤ D ≤ 1.29) and high conversion within one hour. The study highlights the advantages of longer-wavelength light, particularly NIR, for large-scale polymerization in dispersed media due to its superior penetration. The mechanism involves the reduction of the ATRP deactivator at the water/organic interface, generating an activator that initiates polymerization and controls radical propagation through a reversible redox equilibrium between Cu(I) and Cu(II) complexes. The use of MB⁺ as a photocatalyst offers excellent oxygen tolerance and precise control, eliminating the need for rigorous deoxygenation. The polymerization was successfully demonstrated in various reactor sizes, with NIR light showing superior performance even in larger reactors. The results demonstrate the potential of NIR-driven miniemulsion ATRP for rapid, controlled, and oxygen-tolerant polymerization in dispersed media, offering a greener and more practical approach for industrial applications. The method allows for varying degrees of polymerization with high control and enables temporal control of the polymerization process, making it a valuable contribution to the field of emulsion polymerization.