The inhibition effect of the synthetic nonionic surfactants (NIS) on the dissolution of carbon steel in 0.5 M H2SO4 solution has been demonstrated using different techniques. NIS compounds were characterized by IR and 1H NMR spectra. Corrosion parameters resulting from the techniques used confirm that inhibiting power of NIS compounds was increased with increasing NIS compounds, lowering temperature and surface properties e.g., surface tension, interfacial tension and critical micelles concentrations. Low values of surface properties increase the adhesive strength between NIS compounds and the carbon steel surface, which improves the adsorption process. Adsorption of NIS compounds is spontaneous and obeys Temkin’s isotherm. The high inhibition efficiency of NIS compounds depends on the presence of more electron donor atoms, which increases the electron density at the adsorption center. Some thermodynamic functions have been identified and interpreted.