The purpose of this study was to investigate the effects of ethical climate on the use of deception during negotiation for both individuals and groups. While there have been studies published on the effects of ethical climate on decision making at the individual level, there is a gap in the literature on these effects at the group level. Participants were 550 undergraduate students who earned course credit. Participants engaged in a simulated negotiation task about the selling/purchase of a new car, via an instant messenger program. Those assigned to the "seller" role either negotiated individually or as a three-person group, and received one of three ethical climate manipulations (honesty, competitive, or control). The main dependent variable was whether the seller(s) disclosed information about a possible defect. As predicted, groups were less honest than individuals. Although participants were more likely to disclose the defect in the honesty as opposed to the competitive climate conditions, the main effect was not significant. There was a significant interaction effect such that individuals and groups differed in their use of deception in the control condition, but not in the honesty and competitive conditions. While there have been studies published on the effects of ethical climate on decision making at the individual level, this is one of the few studies to address this issue where groups are the decision-making units.