<p>This study developed a reliability-based framework to assess soil slope stability under subsurface blast loading. A log-spiral rotational failure mechanism was adopted to model the critical slip surface, and blast-induced stresses were represented using a distance-dependent attenuation model. Driving and resisting moments along the failure surface were formulated to compute the factor of safety under combined gravity and explosion loading. Uncertainty in soil unit weight, cohesion, and internal friction angle was explicitly considered by modeling these parameters as random variables. Monte Carlo simulation was applied to estimate the probability of failure and the reliability index of slopes subjected to different explosion intensities, burial depths, and source locations. The results showed that increasing explosion pressure significantly reduced the factor of safety and reliability, particularly for steep slopes and shallow explosions. Deeper buried explosions, at depths exceeding the slope height, exhibited a stabilizing effect by reducing the driving mass and generating favorable stress components. Finite element stress analyses confirmed that, for sufficiently deep explosions, blast-induced stresses remained localized and did not intersect the critical slip surface. The proposed framework provided a rational probabilistic measure of slope stability under extreme subsurface blast loading conditions.</p>