Slice the spaghetti squash into roughly 2 inch rings then scoop out the seeds using a spoon.
Brush the flesh of the spaghetti squash with melted butter and season generously on both sides.
Grill the squash over direct heat for a few minutes per side then move to indirect heat for the rest of the cook. Looking for a grill temp of between 325-350 degrees F.
Check for doneness by pinching the flesh of the squash looking for the fibers to separate easily. If the fibers are still tough continue cooking until the fibers separate with little tension.
Brush bbq sauce onto the spaghetti squash rings, cook for just a few more minutes to let sauce set up.