Afghan nationals are not using or maintaining USG-funded development projects in two provinces/PRTs critical to U.S. success. As such, this monograph seeks to answer whether USG development projects in Afghanistan are sustainable. To do so, it analyzes how USG development projects are currently being used by Afghans in Nangarhar and Laghman. These two semi-permissive provinces have alternatively served as sanctuaries for the Taliban and al-Qaeda and as safe havens for USG troops conducting kinetic operations. Next, it assesses the three main reasons Afghans are not using or maintaining projects in these provinces. Then, it examines USG-funded development and sustainability historically, highlighting the differences between development delivery in permissive environments in the Balkans and non-permissive and semi-permissive environments in Afghanistan. Finally, the monograph considers the USG's role in implementing development in Afghanistan and answers whether development in an active war zone can be sustainable and enduring. The primary finding of this monograph is that both non-permissive and semi-permissive provincial security environments pose nearly insurmountable challenges to sustainable development. The basic operating environment must be safe and secure for Afghans to use and maintain USG-funded projects in the long-term. Thus, the presence or influence of insurgents and the level of insurgent activity in those provinces must be minimal to nonexistent. Secondary findings suggest that systemic issues, like the lack of Afghan institutional capacity, endemic corruption, and bureaucratic confusion all work to restrict PRT personnel from incorporating Afghan government officials in long-term project design and planning. This leads to a lack of buy-in by the government which belies sustainability of these services in the long-term. It therefore bodes ill for the overall achievement of USG objectives within Afghanistan.