The article deals with the Lithuanian Army Headquarters’ defence plans for Klaipėda Region (Memel Territory) and Klaipėda City against Germany of the 1930s, providing options of implementation in the event of a military conflict between Lithuania and Germany. The article also provides the data on the Lithuanian armed forces at disposal in 1939, the size of the forces deployed in Klaipėda Region and on its borders, the Army Headquarters plans to use the said military forces, and the potential scenarios of the events. In terms of the military doctrine, an overview of the condition and its potential significance for the sea frontier defence of the Lithuanian Navy is given.