The Piper plane crashed at 17:00 (1500 GMT) on a meadow near Dortmund in the western German state of North Rhine-Westphalia.
Two men, two women and one child were killed. Three other children were seriously injured and transferred to hospital by a helicopter, reported Westdeutsche Allgemeine Zeitung newspaper, citing police source.
The accident site lies between the cities of Wickede and Frondenberg, a spokesman said. Some of the victims were trapped in the crashed plane and had to be freed. Tens of rescuers, several vehicles and helicopters were on site.
The plane was apparently approaching a small region airport nearby, said the newspaper. According to witnesses, it touched a tree shortly before the crash.