Lothar Johann Reinhard von Metternich (23 August 1551 – 17 September 1623) was the Archbishop-Elector of Trier from 1599 to 1623.

Lothar von Metternich was born in Schloss Vettelhoven in Grafschaft on 31 August 1551, the son of Johann von Metternich (1500-1562), Lord of Vettelhoven and bailiff of Saffenberg, and his fourth wife, Katharina von der Leyen zu Adendorf (1528-1567).

In addition to his native German, he was fluent in Flemish, French, Italian, and Latin.

Following the death of Archbishop of Trier Johann von Schönenberg, the cathedral chapter of the Cathedral of Trier elected Metternich as coadjutor archbishop on 7 August 1599.

Metternich's chief goal as archbishop was to improve the finances of the Archbishopric of Trier.