<p>With the increasing environmental concerns for petroleum-based epoxy resins, the development of low-carbon epoxy systems has increased. The traditional epoxy resins are extremely carbon intensive because of the high curing energy and base material as petroleum derived product. Thus, sustainable alternatives are being studied such as green curing methods, bio-based hardeners, solvent free processes, renewable reinforcements and bio-based epoxies from vegetable oils, lignin and sugars. The current review highlights an extensive investigation into major emission sources that arise during the production and manufacturing of epoxy resins and composites. Various emissions from fossil fuel-based precursors, hardeners, process-related energy consumption, and reinforcing substances have been analysed in detail. Furthermore, various novel approaches to achieve low-emission epoxy resins by employing bio-derived precursors, renewable resources, green and bio-based curing agents, energy-saving and solvent-free manufacturing processes, as well as natural or recycled reinforcements have been reviewed. Besides, the review provides an overview of the state-of-the-art research on the LCA of bio- versus petroleum-based epoxy systems, compares their carbon footprints and energy consumption, and presents case studies and sustainability databases. Circular strategies of epoxy resins are another significant focus of the paper, as it highlights the importance of recyclability and reprocessability of thermosets, dynamic covalent and vitrimeric epoxy networks, and epoxy resins’ degradation and recycling methods.</p>