An active wavelength stabilization and scanning system is described which reduces the dye laser wavelength fluctuation under feedback by detecting the changes in the fringe diameter of a temperature‐stabilized Fabry–Perot interferometer with the help of two photodiodes. An estimate of the wavelength drift due to thermal effects is made. Short‐ and long‐term fluctuations in the wavelength, monitored by recording iodine fluorescence are reported. The system response to a sudden external disturbance to the wavelength was studied.