The presented paper discusses the summary of the special issue consisting of 13 peer-reviewed papers regarding Redefinition of SI Units and Its Implications. The papers discuss state-of-the-art reviews and progress made as of now and ongoing progress regarding the redefinition of SI units at different National Metrology Institutes (NMIs) and academic/ research institutes across the globe. Different methodologies adopted while investigating redefinition of SI units have been discussed and summarized by the researchers, which will serve as a pivotal point in guiding the researchers in upcoming time.