Combine first 3 ingredients in a large zip-top plastic bag. Add squash; seal bag, and let stand 1 hour, turning bag occasionally.
. Prepare grill.
. Remove squash from bag, reserving marinade. Place squash on grill rack coated with cooking spray; cover and grill 4 to 6 minutes on each side or until squash is tender. Place squash on a serving platter; sprinkle with salt and pepper. Drizzle with reserved marinade.