A silver halide photographic light-sensitive material comprising a support having component layers thereon including at least one light-sensitive layer containing a silver bromoiodide emulsion, said silver bromoiodide emulsion consisting primarily of twinned silver bromoiodide grains comprising at least a core, an intermediate shell, and an outer shell,
- wherein, in an X-ray diffraction curve obtained by subjecting said silver bromoiodide grains to (420) X-ray diffraction with a CuK.alpha. ray, a length of an intercept drawn horizontally through said curve at a point of 0.13 times a height of a highest peak in said curve is not less than 1.5.degree. of diffraction angle (2.theta.).