The paper reports results from an Ultimatum Game experiment with asymmetric information where Proposers can send to Responders misleading information about their endowment. We allow for all possible gender combinations in the Proposer-Responder pairs. Proposer messages that underestimate the actual amount are quite widespread. The frequency of lying is slightly higher in mixed groups. Conditional on lying, men tend to state bigger lies than women. On the other hand, women tend to tell smaller lies when paired with men than when paired with women. In general, women present higher acceptance rates than men. 1 In the paper by Dreber and Johannesson (2008), receivers were informed about the gender of the sender, but the latter did not know that senders will get this information. Thus the decision of the sender, whether to lie or not, could not be influenced by the gender of the partner.2 Experimental economics have shown that men tend to be less risk averse than women (Croson and Gneezy (2009); Eckel and Grossman (2008)), and also have a stronger preference for competition (Niederle and Vesterlund (2007, 2011);Croson and Gneezy (2009)). Both these personal characteristics support the assumption according to which that men would adopt more aggressive communication strategies than women.3 The Ultimatum Game was developed by Güth et al. (1982). See Güth and Kocher (2014) and van Damme et al. (2014) for recent surveys. The asymmetric information version was introduced by Mitzkewitz and Nagel (1993) and was further extended by many other scholars. 4 The strategy to overstate the endowment is hard to justify in this game, since Proposers who adopt it not only would bear the lying cost, but also would see chances to see their offer accepted falling.