In a saucepan over medium heat, bring rhubarb, water and sugar to a boil. Cook, uncovered, until rhubarb is tender, 6-8 minutes. Remove from the heat; stir in gelatin until dissolved. Stir in orange zest and juice.
Chill until mixture begins to thicken. Fold in strawberries. Pour into a 2-qt. bowl; chill until set.