Last Updated on April 7, 20214. Rottweilers It should not come as a surprise that Rottweilers are on the blacklist of the most dangerous dogs in the world. This is an aggressive dog breed that caused the demise of 45 people in the last few years. So, if you’re not planning to pour your blood, sweat, and tears into training this dog, then you should just not get one for yourself or your family. 5. Bullmastiff The Bullmastiff is a highly intelligent, athletic, and energetic dog. This dog breed is naturally aggressive, so it was involved in 14 fatalities in the years 2005-2017 in the United States. Bullmastiffs are generally excellent guard dogs because of their temperamental personality, but they first have to be trained very to become obedient, well because they’re quite the aggressive dog breed! That was your list of the most aggressive or dangerous dog breeds in the world, so make sure to pick your next pup wisely!