Men typically predict women’s sexual intentions to be higher than women say they are (Haselton & Buss, 2000). It is debated whether this cross-sex bias is because of men overestimating women’s intentions (Murray et al., 2017), women underreporting their own intentions (Perilloux & Kurzban, 2015, 2017), or both. To unify the current debate, we decompose the part of the bias attributable to women underreporting versus men overestimating by using a survey method intervention to reduce underreporting of sensitive information: eliciting estimates about others before sensitive self-reports. First, we calibrate the current measurement instrument to assess the overall size of the misprediction bias (Study 1). Then, we manipulate the order-of-elicitation of self- and other-reports (Studies 2 and 3): Women report significantly higher own sexual intentions when they are asked about other targets’ intentions before their own, suggesting that 48 to 69% of the overestimation bias is attributable to women underreporting their own sexual intentions. Analogous analyses for the misprediction bias about men suggest that women’s overestimation bias of men’s sexual intentions is entirely because of men underreporting their own sexual intentions. The findings have important implications for the current debate in the literature on cross-sex misprediction biases and the literature on asking sensitive survey questions.