In a large skillet, brown the ground beef. Remove beef with a slotted spoon and discard fat.
Return skillet to stove, heat olive oil over medium-high heat. Stir in mushrooms, green and red peppers, squash, onion, paprika, basil, garlic salt, and pepper; cook for five minutes, stirring occasionally.
Reduce heat to medium. Stir in beef and tomatoes; simmer about 20 minutes, stirring occasionally.