Children make choices between generosity and greed every day. Often they must also choose between confession or denial of antisocial acts like greed, thereby displaying either honesty or hypocrisy. Such choices pose cognitive challenges that, in theory, might reflect children's developing social-cognitions and affect their daily social lives and developmental opportunities. Individual differences in altruism and hypocrisy were examined in relation to theory of mind (ToM) in 102 school-age children (44 autistic; 58 typically developing) using ecologically valid altruism and hypocrisy tests where generosity had lasting real-life costs and hypocrisy was self-serving. Selfless altruism was abundant for autistic and nonautistic children alike and was significantly predicted by ToM over and above other predictors like age, gender, and language. More nonautistic (74%) than autistic children (41%) displayed hypocrisy, although individual ToM differences among ASD children were not significantly correlated with it. Findings extend to new instances (altruism and hypocrisy) evidence of ToM's importance for everyday social behaviors that impact upon peer relations while also extending past evidence that: (a) unexpected sociomoral strengths can coexist with ToM delays, (b) attention to individual differences is crucial, and (c) autistic children's capacity to develop sociomoral reasoning should not be underestimated.