Fereydunkenar county hosts millions of migratory birds in the southern parts of the Caspian Sea in the second half of every year. Despite the global prevalence of environmental crime, there is still a dearth of large-scale, empirical analyses of environmental crime in the Middle East. This study compared two well-established criminological frameworks rooted in social learning (neutralization theory and differential association theory) to compare four environmental crimes in Iran: illegal bird hunting, fishing without a license, water pollution, and soil pollution. We surveyed male villagers (N = 400) in the county of Fereydunkenar, which is located in the Mazandaran Province of Iran and hosts millions of migratory birds every year. Variables from neutralization theory (condemnation of the condemners, denial of victim and injury, and appeal to higher loyalty) and differential association theory (frequency of differential association with family and friends, and intensity of differential association) were measured. Approximately 75% of respondents had engaged in illegal bird hunting and nearly 53% of respondents had engaged in fishing without a license. However, water and soil pollution behaviors among the respondents were at low levels. The independent variables explained ∼53, 20, and 18% of the variance in the variables of water/soil pollution, illegal bird hunting, and illegal fishing, respectively. The frequency of differential association with family and intensity of differential association had the largest influences on illegal bird hunting and illegal fishing. The intensity of differential association, appeal to higher loyalty, and condemnation of the condemners had significant positive effects on water and soil pollution behaviors. Based on our models, we concluded that, compared to neutralization variables, differential association variables had greater effects on numerous environmental crimes in Iran.