Open the non-fat greek yogurt and give it a stir. Sometimes it can be watery when you first open it - that's normal.
Dump the packet of Hidden Valley Ranch into the greek yogurt container and mix well.
For best results, make ahead and refrigerate for 6 or more hours so flavors blend together well. Better tasting if made 24 hours ahead of time.
Serve with your favorite veggies or chips.