The single-phase, cubic-structured Ba3La(PO4)3 ceramics were synthesized using the traditional solid-state reaction method. The ceramic sintered at 1375 °C exhibited a relative density of 95.4 %, indicative of a dense microstructure and excellent sintering characteristics. Furthermore, they displayed remarkable microwave dielectric properties: εr = 9.54, Q × f = 32820 GHz, and τf = −43.1 ppm/°C. In addition, the relative density is positively correlated with εr and Q × f of ceramics. According to the complex chemical bond theory, the ionicity of the Ba/La–O bond has a more significant impact on the εr, while the lattice energy and bond energy of the P–O bond respectively dominate the Q × f and τf values. Moreover, the results from Raman spectroscopy indicate that several prominent Raman bands are associated with the vibration of the P–O bond. These findings suggest that Ba3La(PO4)3 ceramics hold promise for applications in high-frequency microwave communication.