This　paper　presents　experimental　investigations　on　the　flexural　behavior　of　double-layer　toughened　sandwich　glass　with　trilateral　simple　support.　A　total　of　sixty-four　pieces　of　toughened　sandwich　glass　with　different　thickness　of　single　layer,　supporting　width,　and　loading　length　were　subjected　to　out-of-plane　flexural　loading　tests.　It　was　demonstrated　that　the　specimens　failed　with　all　pieces　of　cracks　combined　together　as　an　entire　unit　rather　than　to　separate　into　a　large　number　of　glass　fragments.　The　cracks　appeared　only　at　the　lower　layer　of　toughened　sandwich　glass　and　the　upper　layer　of　the　toughened　sandwich　glass　was　integral　and　undamaged.　The　ultimate　capacity　and　flexural　rigidity　of　the　toughened　sandwich　glass　are　enhanced　with　increasing　the　thickness　of　single　layer,　supporting　width,　and　loading　length.　Among　all　studied　parameters,　the　thickness　of　single　layer　exerts　the　largest　influence　on　the　ultimate　capacity　and　flexural　rigidity　of　toughened　sandwich　glass,　while　the　effect　of　supporting　width　is　quite　limited.　A　simplified　design　formula　was　put　forward　to　predict　the　ultimate　capacity　of　double-layer　toughened　sandwich　glass　with　trilateral　simple　support　under　out　of-plane　flexural　loading,　which　was　verified　to　be　reasonable　and　accurate.