The Southeast Anatolia Project, known by its Turkish acronym of GAP (Güneydo?u Anadolu Projesi), is one of the largest regional development projects in the world. The development program’s most prominent work is a series of massive hydroelectric dams and irrigation projects on the Euphrates and Tigris Rivers. However, the project extends far beyond water infrastructure in its remaking of the economic life and environment of nine Turkish provinces. Hospitals, airports, community centers, and schools are also part of the GAP. Indeed, scholars and activists have noted how the GAP became the “economic solution” to the problems of Kurdish resistance in Anatolia. Yet, to call the GAP a Turkish project would be a misnomer: international agencies financed many projects, which in turn employed international experts and multinational corporations. To obtain this support and funding, the GAP administration, organized in the late 1980s, sought to frame the project and the technology of the dam within broader, globalized discourses of security and sustainability. Security discourses produced and activated a range of boundaries, often depending on binary constructions, such as water security/insecurity, border security/insecurity, economic security/insecurity. Meanwhile, as awareness of climate change and other environmental degradation grew in the 1990s, the GAP became “sustainable.” Indeed, the project’s Wikipedia page now announces that the GAP is “based on the concept of sustainable development,” despite its reliance on massive dams known to produce myriad negative environmental effects. Notions of sustainability produced other binaries (sustainable/unsustainable), but also rendered the project within the language of a globalized, and increasingly corporate, environmentalism. Such framings were critical as funding agencies’ priorities shifted, though, ultimately, the GAP itself hardly changed; a huge dam, the Il?su, now rises on the Tigris River. The two discourses seemed, then, to enfold and support one another. “To secure” and “to sustain” meant much the same thing to the GAP administration: economic “development” imposed from above. This paper will examine memoirs, parliamentary reports, and official publications from the 1990s to trace how the GAP administration adapted to changing discourses on security and sustainability. It will also critically analyze the GAP administration’s efforts in relation to an increasingly prevalent body of literature: studies connecting environmental change to international security. A genealogy of these connected discourses in the case of the GAP is critical to understanding how and why their entanglement may in fact hinder conflict resolution and environmental resilience.