Preheat your oven to 350°F (175°C).
In a medium bowl, stir together the crushed gingersnaps, sugar, and melted butter until well combined.
Press the mixture firmly into the bottom and up the sides of a 9-inch pie dish.
Bake the crust for 8 minutes, then remove it from the oven and let it cool slightly.
In a large bowl, whisk together the pumpkin, sweetened condensed milk, eggs, and spices until smooth.
Pour the filling into the cooled crust.
Bake for 45–50 minutes, or until the center is just set and doesn’t jiggle when you nudge the dish.
Let it cool at room temperature, then chill in the refrigerator for at least 2 hours before serving.