Abstract <p>In this work, the Raman and infrared phonon modes of tetragonal metallic double-perovskite Sr₂FeOsO₆ with space group <i>I</i>4/<i>m</i> have been studied utilizing short-range force constant model. Multiferroic materials present a great deal of promise for cutting-edge technology. Development of quantum computing technology, memory devices, data storage all depend on the efficient management of the interaction between ferroic orders. Understanding the thermal, electrical, and magnetic characteristics of double perovskite oxides requires lattice dynamics analysis. This paper used three bending and six stretching force constants to determine zone-center phonons computationally, using normal coordinate analysis. The optical vibrational frequencies for Sr₂FeOsO₆ compounds in the <i>I</i>4/<i>m</i> phase have been first reported using Wilson’s GF-Matrix method. The phonon modes calculated in this research work have been compared with the already available empirically observed frequencies from the literature. Potential energy distributions and the influence of bending and stretching force constants towards various frequencies have been examined in the tetragonal structure of Sr₂FeOsO₆ compound.</p>