First, use a lime wedge to dampen the rim of your margarita glass. Dip the rim into cinnamon sugar.
Fill the cocktail shaker with ice.
Add the tequila, lime juice, triple sec, pumpkin puree, pumpkin spice, and agave syrup to the shaker.
Shake well until mixed and chilled.
Strain the mix into the prepared margarita glass.
Garnish with a lime wedge on the side of the glass.