The above chart measures data for the nations of the Organization for Economic Cooperation and Development, which includes all Western countries plus Turkey, Israel, Chile, Japan, and South Korea. I did not include Mexico, which has about triple the U.S. rate due in large part to the ongoing drug war.
The rate in several developing countries, particularly in Latin America, is significantly higher. Honduras, which has been called the murder capital of the world, has an average firearm murder rate that's about 20 times America's. But make no mistake: For a rich, developed country, the U.S. gun-related homicide rate is very, very high.