Berengar I is a 9th-century nobleman of East Francia, a son of Gebhard, Count of Lahngau, and younger brother of Udo.

He and his brother are created Margraves of Neustria by Charles the Bald in 861.

He is possibly a Conradine, a relative for sure of Adalard the Seneschal, a Girardid.

Berengar is probably the namesake of Berengar II of Neustria, who is probably the son of Berengar I's successor, Henry of Franconia.