${\mathrm{Mn}}_2{\mathrm{Bi}}_2{\mathrm{Te}}_5$, a layered magnetic topological insulator, provides an ideal platform for studying the pressure-tuned interplay between magnetism and topology. Using first-principles density functional theory and Monte Carlo simulations, we examine its structural, magnetic, and electronic evolution under hydrostatic pressures up to 18 GPa. The lattice compresses anisotropically without crystallographic symmetry breaking, and the A-type antiferromagnetic ground state remains robust, with uniaxial anisotropy that favors the $z$ axis throughout. An approximate Mn–Mn crossover distance of 4.15 Å accounts for the sign change of the in-plane exchange coupling $J_2$ over 3 GPa to 6 GPa, thereby reconciling partial deviations of the computed exchange parameters with the Goodenough-Kanamori-Anderson rules. We find no evidence for exchange cancellation within a nonuple-layer unit; instead, the interplane exchange couplings $J_1$ and $J_3$ increase cooperatively under pressure. The Néel temperature nearly doubles, rising from 21 K to about 40 K at 18 GPa, consistent with a fourfold increase in magnetic anisotropy energy and strengthened interplane exchange couplings. Electronically, pressure removes the ambient band inversion by a few gigapascals and drives the bulk gap toward closure between 18 GPa and 19 GPa. Overall, these results demonstrate that hydrostatic pressure simultaneously enhances magnetic order and tunes band topology in ${\mathrm{Mn}}_2{\mathrm{Bi}}_2{\mathrm{Te}}_5$, establishing it as a model system for pressure-controlled magnetism-topology interplay in layered quantum materials.

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• Exchange interaction
• Magnetic order
• Magnetism
• Pressure effects
• Magnetic insulators
• Topological materials
• DFT+U