<p>In this study, the micellization behavior of the synthesized surface-active ionic liquid (SAIL), 1-tetradecyl-3-methylimidazolium bromide ([C₁₄mim]Br), was investigated in aqueous deep eutectic solvents (5 wt%, 10 wt%, and 15 wt%) using conductivity, surface tension, and dynamic light scattering (DLS) techniques. Two polyethylene glycol-based DESs with citric acid (CA) or malonic acid (MA) were prepared and characterized using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The critical micelle concentration (CMC) of the synthesized SAIL was determined and CMC of SAIL increase due to SAIL–DES interactions which is dependent upon the concentration of DESs. Thermodynamic parameters, standard enthalpy of micellization (ΔH°ₘ), standard Gibbs free energy of micellization (ΔG°ₘ), and standard entropy of micellization (ΔS°ₘ), were calculated and discussed. Surface tension measurements were further used to evaluate parameters such as the CMC, surface tension at CMC (γ_cmc), surface excess concentration (Γ_max), surface pressure (π_cmc), and minimum area per molecule (A_min) in the presence of both DESs. The results suggest that the addition of DES enhances the surface activity of the SAIL, with adsorption being more dominant than micellization. Furthermore, the effect of DESs on micelle size was studied using DLS. The findings of this study are expected to be useful for understanding colloidal systems involving SAILs and hydrated DESs.</p>