Tamil Nadu’s 2021 Assembly election resulted in a clear victory for the DMK-led alliance, which won 159 seats out of 234, while the AIADMK-led alliance secured 75 seats. The election was a classic bipolar contest, with DMK receiving around 45% vote share and AIADMK close to 39%. This approximately 6% vote gap proved decisive in determining the outcome. Despite visible vote shares from smaller parties such as the BJP, Congress, Naam Tamilar Katchi, Makkal Needhi Maiam, and AMMK, the election remained firmly between the two major alliances. Tamil Nadu’s political structure continued to reflect alliance-based consolidation rather than fragmented multi-party outcomes. Voters showed a strong tendency toward positive voting behaviour, where preference for parties played a greater role than anti-incumbency sentiment. Party identity remained the dominant factor over candidate influence. The election also highlighted how vote efficiency and distribution across constituencies determine seat outcomes in Tamil Nadu’s tightly structured electoral system.