There is no definitive answer to this question as it depends on the individual. Some 13 year olds may be taller than others due to a variety of factors, such as genetics, nutrition, and exercise. However, on average, boys tend to be taller than girls at this age. Additionally, those from certain ethnic groups may also be taller than average. For example, according to the Centers for Disease Control and Prevention (CDC), the average height for a 13-year-old boy in the United States is about 5 feet 9 inches tall, while the average height for a 13-year-old girl is about 5 feet 4 inches tall. Therefore, if we are looking at tallest 13 year olds in general terms, boys are more likely to fit this description than girls. However, there will always be exceptions to any rule and there are bound to be some extremely tall girls and short boys out there!