Rinse the rice under cold water until the water runs clear.
Place the rinsed rice, milk, sugar, cinnamon stick, vanilla extract, and butter into the crockpot.
Stir the mixture to ensure the sugar is fully dissolved and ingredients are well combined.
Cover the crockpot with its lid and set to cook on high for approximately 2 hours and 30 minutes, or until the rice is tender and the mixture has thickened to a creamy consistency.
Once cooked, remove the cinnamon stick and serve the rice pudding warm.