Thermodynamic behavior of dodecyltrimethylammonium bromide (DTAB) in sodium carboxymethyl cellulose (NaCMC) solution with and without methyl orange (MO) dye in the ethanol–water mixture (0, 0.1, 0.2, and 0.3) volume fractions of ethanol at different temperatures by conductivity measurements is studied. The obtained conductivity data suggests that the value of α, CAC, and CMC* for the MO + NaCMC + DTAB system decreases when compared to the NaCMC + DTAB system. MO + NaCMC + DTAB system shows more negative , , , and and more positive values in contrast to the comparable values for the NaCMC + DTAB system. These results demonstrate the thermodynamic feasibility and spontaneity of micellization with MO in the ethanol–water mixture. Nonetheless, as the temperature and the percentage of ethanol in the volume increase, so do the α (degree of dissociation), CAC (critical aggregation concentration), and CMC* values. A valuable insight into the thermodynamic stability, fluidity, solvent structure, polarity of the solvent, and interaction degree in ethanol–water mixture with and without MO may be gained from varying with different solvophobic and solvent parameters.