This study investigates the influence of friction on the buckling behavior of thin, elastic, spherical shells under uniform external pressure. The study spans a range of geometric parameters, from shallow shells to hemispheres. Three different end-edge boundary conditions—clamped, hinged, and frictional ends—are considered across a wide range of friction coefficients using an axisymmetric model and nonlinear buckling analysis. The spherical shell becomes increasingly susceptible to buckling when the friction coefficient falls below the converged friction coefficient. A formula is developed to estimate this converged friction coefficient for each geometric parameter. Furthermore, a boundary separating the effects of friction on critical pressure into distinct regions is established, and equations predicting critical pressure within each region are provided. The study also finds that friction influences the buckling mode transition in the shells. Due to significant changes in the theta angle of the no-bending point with increasing geometric parameter and friction coefficient, buckling mode transitions occur at lower friction coefficients in wider spherical shells. These findings provide valuable insights into the intricate interplay between geometric parameter, friction, and buckling behavior in shells. In practical applications, this study can be used to assess and enhance the safety and reliability of spherical shells.