The heritability of human behavior can be estimated through studies comparing MZ and DZ twins and through adoption studies. Meta-analyses have estimated the heritability of intelligence, mental chronometric performance, language ability, anxiety disorders, major depression, antisocial behavior, problem drinking, and smoking. This article presents the aggregation and analysis of these meta-analyses, which included a total of over four hundred samples. The results of the aggregation suggest that about 41% of human behavior is genetically influenced, a percentage that may have evolutionary value. Some significant moderators were found in more than one meta-analysis, including greater heritability (a) in more disordered levels of a behavior for performance on a language-ability test, antisocial behavior, and smoking and (b) in females for antisocial behavior and smoking initiation. The moderator findings raise questions about what might explain the identified differences in level of heritability.