We extend the study of superinstantons presented in (Kimura and Pestun in superinstanton counting and localization, 2019) to include orthosymplectic supergroup gauge theories, B-n0 vertical bar(n1), C-n, and D-n0 vertical bar(n1). We utilize equivariant localization to obtain the LMNS contour integral formula for the instanton partition function, and we investigate the Seiberg-Witten geometries associated with these theories. We also explore the brane configurations involving positive and negative branes together with O-planes that realize the orthosymplectic supergroup theories.