Natural American Spirit (NAS) cigarettes feature a pro-environment marketing campaign on the packs. The NAS "Respect for the Earth" campaign is the first example of on-the-pack corporate social responsibility advertising. In a randomized survey design, we tested perceptions of NAS relative to other cigarette brands on harms to self, others, and the environment. Never (n = 421), former (n = 135), and current (n = 358) US adult smokers were recruited for an online survey from January through March 2018. All participants viewed packs of both NAS and Pall Mall. Participants were randomized to view NAS vs. Pall Mall and to pack color (blue, green, or yellow/orange), which was matched between brands. Survey items assessed perceptions of health risk of the cigarette brand to self, others, and the environment and corporate perceptions. Consistently on all measures, NAS cigarettes were rated as less harmful for oneself, others, and the environment relative to Pall Mall (p's < .001). Though Reynolds American owns both brands, participants rated the company behind NAS as more socially responsible than the company behind Pall Mall, F[1, 909] = 110.25, p < .001. The NAS advantage was significant irrespective of smoking status, pack color, and brand order, with findings stronger for current than never smokers. Pro-environmental marketing on NAS cigarette packs contributes to misperceptions that the product is safer for people and the environment than other cigarettes and made by a company that is more socially responsible. Stricter government regulations on the use of pro-environment terms in marketing that imply modified risk are needed.