Humans　are　social　animals,　but　not　everyone　will　be　mindful　of　others　to　the　same　extent.　Individual　differences　have　been　found,　but　would　social　mindfulness　also　be　shaped　by　one＇s　location　in　the　world?　Expecting　cross-national　differences　to　exist,　we　examined　if　and　how　social　mindfulness　differs　across　countries.　At　little　to　no　material　cost,　social　mindfulness　typically　entails　small　acts　of　attention　or　kindness.　Even　though　fairly　common,　such　low-cost　cooperation　has　received　little　empirical　attention.　Measuring　social　mindfulness　across　31　samples　from　industrialized　countries　and　regions　(n　=　8,354),　we　found　considerable　variation.　Among　selected　country-level　variables,　greater　social　mindfulness　was　most　strongly　associated　with　countries＇　better　general　performance　on　environmental　protection.　Together,　our　findings　contribute　to　the　literature　on　prosociality　by　targeting　the　kind　of　everyday　cooperation　that　is　more　focused　on　communicating　benevolence　than　on　providing　material　benefits.