<p>This study aimed to develop and characterize a binary emulsion gel by a combination of ionic cross-linking (calcium chloride) and heat treatment using sonicated whey protein (SWP) and guar gum (GG). In particular, the influence of GG concentration (0.1–0.3%) and SWP on the structural, mechanical, thermal, and vitamin D₃ encapsulation properties was evaluated. Results demonstrated that the synergistic effect of SWP and GG addition, particularly at 0.2%, significantly enhanced hydrophobic interactions, gel strength, water-holding capacity, and thermal stability. Ultrasound pretreatment of whey protein (WP) promoted the intermolecular interactions in the gel network by inducing protein unfolding, resulting in the formation of a more cross-linked network with enhanced elasticity. Scanning electron microscopy confirmed the formation of compact and uniform microstructures, while excessive GG concentrations (0.3%) led to phase separation and a looser gel structure. The FTIR spectroscopy revealed hydrogen bonding and hydrophobic entanglements between WP and GG during gel formation. The SWP-GG emulsion gels exhibited high vitamin D₃ encapsulation efficiency (up to 96.9%) and improved loading capacity, indicating their potential as effective delivery systems. Overall, the combination of sonicated whey protein and guar gum produced stable and elastic binary emulsion gels with promising applications as effective delivery systems for sensitive bioactives and fat replacers in functional foods.</p> Graphical Abstract <p></p>