In a large bowl, combine the cake mix, pudding mix, water, eggs and oil. With a hand or stand mixer, beat on low speed until well blended. Gently stir in lemon zest and poppy seeds.
Pour into a greased 9-in. x 5-in. loaf pan. Bake loaf for 50-60 minutes, or until a toothpick inserted in the center comes out clean. To prepare lemon glaze, whisk sugar and lemon juice in a bowl, until well blended.
Cool in pan for 5 minutes before removing to a wire rack. Once on wire rack, place wax paper beneath rack and brush loaves with lemon glaze.