Recent reports indicate that Europe may be following America in its trend toward the prevalence of overweight adults, reflecting a globalization of eating patterns. This cross-national study examined the body mass index, calculated as weight in kilograms divided by height in meters squared, in 29 242 children aged 13 and 15 years in the United States and 14 other industrialized countries. The highest prevalence of overweight was found in the United States. The prevalence of overweight in other countries was highest in Greece, Ireland, and Portugal and lowest in Lithuania. These findings have important implications for expected morbidity and mortality rates due to obesity in the coming decades.