Preheat oven to 350°F and line a 9x5-inch loaf pan with parchment paper or lightly grease it.
In a large bowl, combine ground beef, ground pork, breadcrumbs, diced onion, beaten eggs, milk, minced garlic, salt, and black pepper. Mix gently with your hands until just combined, being careful not to overwork the meat.
Transfer the meat mixture to the prepared loaf pan and shape into an even loaf, smoothing the top with your hands.
In a small bowl, whisk together ketchup, brown sugar, and Worcestershire sauce. Spread half of this glaze over the top of the meatloaf.
Bake for 45 minutes, then spread the remaining glaze on top and continue baking for 15 more minutes, or until the internal temperature reaches 160°F.
Remove from oven and let rest for 10 minutes before slicing and serving.