Bodily signals influence high-order cognitive and emotional processes, including social decision making. Here, we examined whether individual differences in the capacity to read signals from inside (interoception) and outside the body (exteroception) predicted participants' (dis)honesty. Deceptive behavior was measured in a card game where participants were tempted to lie to another person for financial gain in two conditions, i.e., under high vs. low risk of being seen by the other player (reputation risk). Participants completed the Heartbeat Counting Task (cardiac interoception) and a variation of the Body-Scaled Action Task (visual exteroception). Overall, when participants believed their reputation was at risk (i.e., the other player knew they lied) they told significantly less egoistic lies compared to when their choices were secret. This effect was significantly moderated by cardiac interoception. While low interoceptive participants told less egoistic lies when their reputation was at risk, high cardiac interoceptive participants did not change their behavior depending on the reputation risk conditions. We also found that cardiac interoception and visual exteroception did not correlate. Together our findings suggest that although integrated, interoception and exteroception constitute distinct facets of corporal awareness, and that high cardiac interoception shapes moral behavior by making people less concerned about their social reputation during spontaneous lies.