The Treaty of Nymphaeum was a peace treaty signed in December 1214 between the Nicaean Empire, successor state of the Byzantine Empire, and the Latin Empire. Although both sides would continue to fight for years to come, there were some important consequences of this peace agreement.

1. First, the peace treaty effectively recognized both parties, as neither one was strong enough to destroy the other.
2. The second consequence of the treaty was that David Komnenos, who had been a vassal of Henry and who had been carrying out his own war against Nicaea with the support of the Latin Empire, now effectively lost that support. Theodore was thus able to annex all of David's lands west of Sinope in late 1214, gaining access to the Black Sea.
3. The third consequence was that Theodore was now free to wage war against the Seljuqs without the distraction of the Latins for the time being. Nicaea was able to consolidate their eastern frontier for the remainder of the century.

Hostilities broke out again in 1224, and a crushing Nicaean victory at the Second Battle of Poemanenum reduced Latin territories in Asia effectively only to the Nicomedian peninsula. This treaty allowed the Nicaeans to go on the offensive in Europe years later, culminating in the reconquest of Constantinople in 1261.