The aim of this study was to determine the effect of different lighting levels on the total protein and amino acid content of the isolated Lyngbya sp. Algal samples were collected from the Euphrates River in Nassiriyah, southern Iraq. The isolated algae were cultivated under optimal laboratory conditions for two weeks, exposed to varying levels of lighting. After this period, protein and amino acid contents were measured. The results revealed significant differences at a probability level of 0.05. The highest total protein content was observed at a luminance level of 100 (72.17%), while the lowest was at a luminance level of 5 (15.11%). Significant differences in amino acid levels were also noted, depending on the lighting intensity. These findings indicate that lighting levels significantly influence both the protein content and the amino acid profile in the dry matter of the Lyngbya sp. samples.