The extant literature recognizes national identity as a pivotal factor motivating both individual and collective actions to tackle environmental problems. Yet, prior research shows mixed evidence for the relationship between national identity and environmentalism. Here, we propose a theoretical approach that articulates distinctions between different forms of national identity and their differential associations with environmental attitudes and behaviors. Specifically, we argue that it is key to differentiate national identification, which reflects a positive attachment to one's country and ties to other compatriots, from national narcissism, which reflects viewing one's country as exceptional and deserving of special treatment. In contrast to national identification, national narcissism is consistently associated with lower environmental concern and predicts support for anti-environmental policies. We show that this is likely due to national narcissism being linked to belief in climate-related conspiracy theories, support for policies that challenge external pressures yet present the nation in a positive light (e.g., greenwashing), and focusing on short-term benefits for the nation. Extending past individual-level findings, we report a pre-registered analysis across 56 countries examining whether national narcissism is also linked to objective indices of lower environmental protection at the country level of analysis. Results revealed a negative relationship between countries' environmental performance and country-level national narcissism (while adjusting for national identification and GDP per capita). We discuss the theoretical and practical implications of our approach and the country-level findings for advancing research in the field.