Abstarct: In this study, La₁₋ₓAxMnO₃ nanoparticles, BaTiO₃ nanoparticles, and La₁₋ₓAxMnO₃–BaTiO₃ nanocomposites with varying Sr and Ba concentrations were synthesized, and their physical properties were then investigated. The La₁₋ₓSrxMnO₃ nanoparticles with different values of x (0.2, 0.3, 0.4, and 0.5) were synthesized by the sol-gel method using mextal acetate precursors. X-ray diffraction (XRD) analysis revealed the formation of a single-phase orthorhombic structure with high crystallinity and crystal sizes ranging from 10 nm to 78 nm as the annealing temperature increased from 650°C to 950°C. Field emission scanning electron microscopy (FESEM) images showed spherical to polyhedral morphologies depending on Sr concentration. Magnetic measurements confirmed ferromagnetic behavior across all samples, with saturation magnetization decreasing and coercive field increasing as Sr content rose, indicating a strong composition-dependent magnetic response. These changes clearly reflect the effect of Sr concentration on the magnetic properties of the nanoparticles. Furthermore, BaTiO₃ nanoparticles were synthesized by the sol-gel method, and their X-ray diffraction pattern indicated the formation of the tetragonal BTO phase. These nanoparticles exhibited a band gap of 3.1 eV, which makes them highly suitable for optoelectronic applications. Additionally, the dielectric properties of BTO nanoparticles were investigated at different frequencies. The analysis of the real dielectric constant behavior at low frequencies showed a large value, whereas at higher frequencies, it decreased. These characteristics were attributed to surface polarization and the Maxwell-Wagner model. La₁₋ₓSrxMnO₃–BaTiO₃ nanocomposites with different strontium concentrations (x = 0.2, 0.3, 0.4, and 0.5) were prepared by mixing and compressing at high temperature. XRD confirmed the coexistence of separate LSMO and BTO perovskite phases. With increasing Sr content, saturation magnetization declined, and coercive field rose. The dielectric properties of the nanocomposites were also examined, and it was observed that the dielectric constant increased at low frequencies and decreased at high frequencies. Among the compositions, the 60La₀.₇Sr₀.₃MnO₃–40BaTiO₃ nanocomposite demonstrated superior dielectric performance and minimal dielectric loss. Next, (1-y)La₀.₇Sr₀.₃MnO₃–yBaTiO₃ nanocomposites with different BTO contents (40%, 60%, and 80% by weight) were prepared. The results showed that with an increase in the amount of BTO, the saturation magnetization decreased, and the dielectric constant increased. Among them, the 40La₀.₇Sr₀.₃MnO₃–60BaTiO₃ nanocomposite was selected as the optimal combination due to its large dielectric constant, low dielectric loss, and better magnetic properties. The effect of replacing Sr with Ba in the LSMO composition was then investigated. Comparing the results of the 40La₀.₇Ba₀.₃MnO₃–60BTO nanocomposite with a similar Sr-baxsed sample revealed that replacing Ba did not improve the magnetic and dielectric properties; rather, it reduced the overall performance of the nanocomposite. The results of this study showed that the 40La₀.₇Sr₀.₃MnO₃–60BTO nanocomposite, due to its large dielectric constant, low dielectric loss, and optimized magnetic properties, is the most suitable option for electronic and multiferroic applications.