Society expects that AI systems used in the real-world will be safe (not harm users or third parties); systems which are not safe will not be allowed by governments and regulators. This chapter examines safety concerns and techniques in NLG, and also looks at software testing, which is used to identify bugs and other problems which could lead to unacceptable behaviour. The chapter concludes with a section on maintaining NLG systems, which is very important (most of the life-cycle costs of software systems are in maintenance) but poorly understood.