Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9x13-inch baking pan.

Combine cake mix, mandarin oranges with juice, eggs, and oil in a large bowl; beat with an electric mixer until smooth. Pour batter into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 35 to 40 minutes. Set aside to cool for at least 30 minutes.

Beat pineapple with juice, whipped topping, and dry pudding mix together in a large bowl until blended. Spread on cooled cake.