A holster for a handgun, comprising: a cavity having an open top end, a bottom end, a frame/slide portion and a trigger guard portion, wherein said frame/slide portion of said cavity has greater depth than said trigger guard portion of said cavity; an axis extending between said frame/slide portion of said cavity and said trigger guard portion of said cavity; wherein said axis extends from said open top end to said bottom end; a lever having a finger button portion and an engagement portion, wherein said lever includes a second side facing generally toward said holster cavity, and wherein said engagement portion of said lever includes a locking projection extending from said second side of said engagement portion; wherein said lever is pivotally attached atop a side wall of said holster, along said axis, approximately between said finger button portion and said engagement portion, such that said finger button portion extends from said axis and is positioned above said frame/slide portion of said cavity and said engagement portion extends from said axis and is positioned above said trigger guard portion of said cavity; one or more ridge segments (518, 519) extending from said side wall around at least a portion of said lever so as to define a recess, wherein said lever is positioned within said recess; and an aperture formed in a portion of said side wall beneath at least a portion of said finger button portion of said lever, wherein said aperture is formed within said recess; wherein said one or more ridge segments includes a locking slider, slidably positioned within said one or more ridge segments, wherein said locking slider is slidable between a locked and an unlocked position, and wherein said locking slider is positioned above said engagement portion of said lever when said locking slider is in said locked position. a cavity having an open top end, a bottom end, a frame/slide portion and a trigger guard portion, wherein said frame/slide portion of said cavity has greater depth than said trigger guard portion of said cavity; an axis extending between said frame/slide portion of said cavity and said trigger guard portion of said cavity; wherein said axis extends from said open top end to said bottom end; a lever having a finger button portion and an engagement portion, wherein said lever includes a second side facing generally toward said holster cavity, and wherein said engagement portion of said lever includes a locking projection extending from said second side of said engagement portion; wherein said lever is pivotally attached atop a side wall of said holster, along said axis, approximately between said finger button portion and said engagement portion, such that said finger button portion extends from said axis and is positioned above said frame/slide portion of said cavity and said engagement portion extends from said axis and is positioned above said trigger guard portion of said cavity; one or more ridge segments (518, 519) extending from said side wall around at least a portion of said lever so as to define a recess, wherein said lever is positioned within said recess; and an aperture formed in a portion of said side wall beneath at least a portion of said finger button portion of said lever, wherein said aperture is formed within said recess; wherein said one or more ridge segments includes a locking slider, slidably positioned within said one or more ridge segments, wherein said locking slider is slidable between a locked and an unlocked position, and wherein said locking slider is positioned above said engagement portion of said lever when said locking slider is in said locked position.