This study investigated the effects of red, blue, and green light wavelengths on tissue regeneration in Dugesia japonica planaria. Over a 19-day period, planaria were exposed to controlled environments with specific light wavelengths, while a control group was maintained under ambient light. Measurements taken at five intervals revealed that all three experimental groups experienced enhanced regeneration compared to the control. Red light promoted steady growth, likely due to increased mitochondrial activity and ATP production. Blue light caused an initial decline in size, suggesting oxidative stress, but ultimately supported regeneration, possibly through stress-response pathways. Green light yielded the most significant final growth, indicating it may stimulate unique regenerative mechanisms. These findings suggest that light wavelength plays a significant role in tissue regeneration, with potential implications for non-invasive regenerative therapies in human medicine.