The analysis of volatile organic compounds (VOCs) is an important issue in various domains. For this, electronic noses (eN) are very promising as novel analytical tools that are portable, inexpensive, and efficient for reliable and rapid analyses. Recently, we have demonstrated that surface plasmon resonance imaging (SPRI) is especially interesting for the development of eNs dedicated for gas-phase analysis of VOCs. To further improve the performance of the eN based on SPRI, in this study, we investigated the influence of the LED wavelength on the sensitivity of the system. For this, a complete theoretical study together with a related experimental investigation for the validation were carried out. We have shown that the wavelength of the light source has an impact on the surface sensitivity of SPRI for the detection of VOCs. Indeed, in the studied wavelength range from 530 nm to 740 nm, both bulk sensitivity and surface sensitivity increase as the wavelength increases with good coherence between theoretical and experimental results. With the optimal LED wavelength, the detection limits of our eN reach low ppb range for VOC such as 1-butanol.