The Gaza war, which began on October 7, 2023, and lasted 15 months, triggered intense global reactions due to the widespread destruction of buildings, hospitals, schools, and the killing of Palestinian civilians by the Israeli army. However, compared to the widespread protests in the West, those in Islamic countries were limited in scale and intensity, showing no signs of igniting Arab nationalism. This raises the question: what factors have contributed to the decline of Arab nationalism in the Middle East? This research hypothesizes that the decline of Arab nationalism results from complex interactions among political, social, and economic factors. A qualitative explanatory method was employed, using library-based data collection. The findings reveal that Arab nationalism has historically faced numerous challenges, including reformist and secessionist movements. Furthermore, the positions of Arab countries and recent developments during the Gaza war have weakened national identity and Arab unity. These countries perceive a new wave of nationalism based on Islamism as a threat to their authoritarian regimes and thus strive to suppress Arab nationalism in the region. Additionally, internal rivalries among Arab states, economic dependence on the West, and the inability to form effective unions are significant contributors to this decline. Consequently, Arab nationalism has gradually been replaced by local and religious tendencies, which in some cases have deepened internal divisions and further weakened Arab solidarity.