In a small saucepan, combine orange juice and sugar. Cook over medium heat, stirring occasionally, for 4 to 5 minutes or until sugar dissolves. Remove from heat, and set aside.

In a medium saucepan, bring 3 cups water to a boil. Add tea bags, remove from heat, and let steep for 20 minutes. Remove tea bags, and discard.

In a 1 gallon pitcher, combine orange juice mixture, tea mixture, and remaining 3 quarts water, stirring to combine. Cover and chill overnight. Garnish with orange slices, if desired.