Heat oil in a skillet over medium heat, stir in the ground pork, stir fry for 2-3 minutes or until changed color, remove from pan and set aside (leave oil in the pan).
Sauté garlic until fragrant, then stir in green, red pepper and onion, stir fry for 1-2 minutes.
Add the pork back into the pan, and toss in the Thai basil leaves.
Season with fish sauce, soy sauce and sugar, turn to medium-high heat and stir fry for a minute.