Mołtajny (German Moltheinen, later Molteinen) - a village in Poland, in Warmia and Mazury District, in Kętrzyn Province, Barciany Community.

In years 1975 - 1998 the village belonged administratively to Olsztyn District

The village is situated at Arklity Lake.

The village was set up between 1374 - 1379, belonged to the Teutonics, which was marked by existing then Teutonic guardian tower in the region of Comtat Viovodeship.

The Teutonic Castle disappeared in Medieval times, probably during the thirteenth-years war. The village came into possession of the Schlieben family till XVII century and in the XVIII century it went under the rule of Egloffstein family. 

Before the World War II across the village there came narrow gauge railway (Rastenburger Kleinbahn), from Kętrzyn to Gierdawa (Żeleznodorożnyj). The Railway was opened in 1917. Before 1939 it was closed because of unprofitability, but the war saved the railway, which was anyway used by the local landowners to transport the harvest and stocks, mainly sugar beetroots to Kętrzyn. In 1945 the Russians disassembled the railway and took it away. 

During the World War II in Mołainy there were war prisoners at work from September Campaign. The prisoners were closed for night in barracks at Arklity Lake. 

In the 70. of XX century, there was agricultural settlement (as blocks) built in Mołtajny with the House of Culture and CO boiler to provide housing to the local inhabitants. The blocks are owned by the Mołtajny Housing Community, which is also administrating the Housing Community in Wopławki. 

Mołtajny is the village council to which also belong: Arklity, Błędowo, Górki, Markuzy. In the years 1973 - 1977 Mołtajny council belonged to Community Skandawa.