The vortex dynamics of an undoped uniaxially textured YBa₂Cu₃O_7−δ (YBCO) superconducting film grown onto a MgO (100) substrate was inspected by applying the vortex glass and collective-pinning models. The texture and structural characterization studied by X-ray diffraction revealed a uniaxially (00 l) YBCO layer, which coexists with minor Y₂BaCuO₅ and CuO phases. The temperature dependence of the magnetization in the superconducting state revealed a critical temperature TC = 88 K. By measuring the hysteresis loops ( M(H)) at 10–70 K, the critical fields HC1, HC2, HP and Hirr were estimated and a vortex matter diagram was sketched. By using the Bean model, the critical current density values JC(T,H) were obtained and the typical peak effect is observed. The vortex dynamics mechanism is discussed taking into account four vortex feature regimes in the double-logarithmical JC(H) curves. The vortex pinning mechanism is discussed by obtaining the pining force, FP, its normalization, f(h), and magnetic relaxation M(t) measurements taken in field cooling mode at 10–60 K. The glassy exponent μ and the characteristic energy U(J, T) in the vortex glass model were estimated following the Maley method. The collective-pinning model is used to discuss the possible vortex regimes mechanism (individual flux lines, small bundles and large bundles of pinned flux). Eventually, the E(J) curves, expressed from the swept field and creep measurements, show a power-law behaviour, in agreement with the vortex matter.