A simple chemical method is developed to produce bulk quantities of nitrogen-doped, reduced graphene oxide (GO) through thermal annealing in ammonia. XPS analysis shows that nitrogen doping occurs at as low as 300°C, with the highest doping level of ~5% achieved at 500°C. Annealing in ammonia also reduces oxygen content, decreasing from ~28% in as-made GO to ~2% in GO annealed at 1100°C. N-doping is accompanied by reduction, with higher temperatures leading to increased quaternary nitrogen (N replacing carbon atoms in the graphene plane). Oxygen groups in GO are responsible for reactions with ammonia and C-N bond formation. Pre-reduced GO with fewer oxygen groups shows reduced reactivity with ammonia and lower N-doping levels. Electrical measurements of GO sheets show that ammonia-annealed GO has higher conductivity than hydrogen-annealed GO, indicating more effective reduction. N-doped reduced GO exhibits n-type electron doping behavior with a Dirac point at negative gate voltages. The method enables the synthesis of bulk N-doped, reduced GO sheets with useful properties not achievable with undoped graphene. Oxygen functional groups, including carboxylic, carbonyl, and lactone groups, are essential for reactions with ammonia to form C-N bonds. The degree of reaction with ammonia and N-doping depends on the amount of these oxygen groups at defect and edge sites. N-doped, reduced GO sheets could be used for further functionalization and various applications, including clean energy.A simple chemical method is developed to produce bulk quantities of nitrogen-doped, reduced graphene oxide (GO) through thermal annealing in ammonia. XPS analysis shows that nitrogen doping occurs at as low as 300°C, with the highest doping level of ~5% achieved at 500°C. Annealing in ammonia also reduces oxygen content, decreasing from ~28% in as-made GO to ~2% in GO annealed at 1100°C. N-doping is accompanied by reduction, with higher temperatures leading to increased quaternary nitrogen (N replacing carbon atoms in the graphene plane). Oxygen groups in GO are responsible for reactions with ammonia and C-N bond formation. Pre-reduced GO with fewer oxygen groups shows reduced reactivity with ammonia and lower N-doping levels. Electrical measurements of GO sheets show that ammonia-annealed GO has higher conductivity than hydrogen-annealed GO, indicating more effective reduction. N-doped reduced GO exhibits n-type electron doping behavior with a Dirac point at negative gate voltages. The method enables the synthesis of bulk N-doped, reduced GO sheets with useful properties not achievable with undoped graphene. Oxygen functional groups, including carboxylic, carbonyl, and lactone groups, are essential for reactions with ammonia to form C-N bonds. The degree of reaction with ammonia and N-doping depends on the amount of these oxygen groups at defect and edge sites. N-doped, reduced GO sheets could be used for further functionalization and various applications, including clean energy.