We investigate the temperature-dependent dynamical properties of PbZrO3 (PZO) using Molecular Dynamics (MD) simulations with an effective Hamiltonian. As temperature decreases from 1800 K to 10 K, PZO is predicted to undergo a sequence of phase transitions. Above 1350 K, it exhibits the cubic paraelectric Pm3m phase. Between 1350 K and 650 K, an intermediate phase emerges, denoted here as the Σ phase and characterized by antipolar displacements along [110] and complex oxygen octahedral tiltings about [001] – both associated with the Σ-point and with amplitudes increasing upon cooling. Below 650 K, PZO stabilizes in the Pbam ground state, exhibiting additional R- and S4-point order parameters, with all associated condensed degrees of freedom strengthening at lower temperatures. MD results yield a first-order character of the Pm3m–to–Σ and Σ–to–Pbam transitions. Moreover, phonon analysis reveals the predicted temperature evolution of mode frequencies associated with Γ, R, Σ, and S4 k-points. In the cubic phase, Σ - mode having both antipolar and octahedral tiltings characteristics is softening on temperature decrease – as consistent with the existence of a bilinear coupling that is often overlooked. In the Σ phase, a mode associated with the R-point-induced anti-phase octahedral tiltings strongly softens. Within the Pbam phase, multiple resonant frequencies appear for each mode, reflecting complex mode couplings, including bilinear and trilinear ones. These computations agree well with experimental data, including temperature-behavior of soft mode and even an higher mode, which calls for testing all present predictions – that may offer new insight into key features of PZO’s including its lattice dynamics and phase transitions.