<p>The effects of Sc and Y microalloying on the microstructure, mechanical properties, and electrical conductivity of Al–Mg–Si alloys are systematically investigated. By integrating microstructural characterization with performance testing, the mechanisms through which microalloying elements influence recrystallization, texture evolution, precipitation behavior, and fracture responses are elucidated. The results show that Sc addition promotes recrystallization and leads to notable grain refinement, along with an increased volume fraction of the strengthening β″ phase. These changes collectively enhance both strength and plasticity, though electrical conductivity is concurrently lowered. Y addition strengthens the alloy by promoting precipitation while improving conductivity through purification of the matrix. However, Y addition decreases the Schmid factor and forms coarse AlY₂Si₂ particles at grain boundaries, which readily initiate cracks and consequently degrade plasticity. When Sc and Y are coadded, the formation of Al(Y,Sc)₂Si₂ and Mg₂Si phases consumes substantial solute atoms, reducing the volume fraction of the β″ phase and limiting precipitation strengthening enhancement. However, the synergistic optimization of texture and grain morphology contributes to significantly enhanced plasticity in the co-modified alloy.</p>