<p>The usage of synthetic plastics in packaging is a significant contributor to environmental pollution. To overcome this concern, focus has now shifted toward natural alternatives that provide comparable protection and are eco-friendly. In place of synthetic polymeric films, soy protein isolate (SPI) films have gained popularity as an environmentally acceptable alternative, but their limited mechanical strength and water resistance have prevented their wider adoption. There is a need to comprehensively analyze the available literature on the impact of modified rubber and acid-functionalized aromatic compounds on SPI films. This review attempts to summarize the effect of modified rubber (such as natural rubber (NR), styrene–butadiene rubber (SBR), and epoxidized natural rubber (ENR)) and acid-functionalized aromatic compounds (benzilic acid, nalidixic acid, phenolic acids, and many others) on different quality parameters of SPI films. The study provides insight into different methods such as solution casting, compression molding, electrospinning, and various others for fabricating films.&#xa0;It further discusses the effect of these additives on the structural and morphological changes as well as material and water resistance properties of SPI films. Lastly, we have discussed the antibacterial efficacy and biodegradation characteristics of functionalized SPI films. This review concludes that the incorporation of modified rubbers and acid-functionalized compounds significantly enhances the mechanical strength and hydrophobic properties of the films. Collectively, this review provides comprehensive knowledge about the effect of acid-functionalized aromatic compounds and modified rubber on SPI films and will guide future research and practical applications of these materials.</p> Graphical abstract <p></p>