In 12" skillet or wok heat oil over high heat; add vegetables and cook, stirring quickly and frequently, until celery and pepper are tender crisp, 1-2 minutes.
Add turkey and stir to combine.
In measuring cup combine water, cornstarch and broth mix, stirring to dissolve cornstarch; pour mixture into skillet and bring to boil.
Reduce heat and cook, stirring until mixture thickens.
Stir in teriyaki sauce.
Cook for 1 minute longer.