Gather all ingredients.

Zest lemons, and place zest into a large glass bottle or jar.

Pour vodka into the bottle. Cover loosely and let infuse for 1 week at room temperature.

After 1 week, combine sugar and water in a medium saucepan and bring to a boil; do not stir. Boil for 15 minutes, then remove from the heat and allow syrup to cool to room temperature.

Stir vodka mixture into the syrup.

Strain into glass bottles, then seal each bottle with a cork. Let age at room temperature for 2 weeks.

Store bottled limoncello in the freezer until icy cold. Serve in chilled vodka glasses or shot glasses.