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Iron-doped barium strontium titanate ceramics represent a significant class of multifunctional ferroelectric materials with tunable dielectric and electrical properties. This study presents a comprehensive investigation of dielectric relaxation mechanisms using impedance spectroscopy, electrical modulus analysis, and Cole–Cole modelling. The incorporation of iron dopants induces structural distortions, modifies crystallite size, and introduces oxygen vacancies, significantly influencing dielectric behaviour. Non-Debye relaxation mechanisms are confirmed through theoretical models such as the Havriliak–Negami model, Cole–Cole formalism, and equivalent circuit analysis. The results reveal that grain boundary effects, defect chemistry, and correlated barrier hopping conduction govern the electrical response of these ceramics