Bring broth to boil in saucepan. Reduce heat to medium-low, cover, and simmer until quinoa is tender and broth has been absorbed, 15-20 minutes. Transfer quinoa to a large bowl and set aside to cool, about 10 minutes.
Mix tomatoes, parsley, olives, onion, feta cheese, olive oil, vinegar, garlic into quinoa. Squeeze lemon juice over salad, season with salt and pepper, and toss to coat. Chill in refrigerator for 1-4 hours if desired.