Aleksas Miliulis, also known by his codenames Neptūnas or Algimantas (1923 – 8 June 1949) was a Lithuanian partisan and a commander of the Kęstutis military district.

He was a captain in the Lithuanian army in the interwar period as well as a teacher in the villages of Budviečiai and later Purvėnai.

After a few months, he became the head of the company's propaganda sector, and in 1948 he was chosen leader of his own subdivision of the military district.

During this period Miliulis succeeded in establishing the underground organization Raketa in Tauragė, whose members included employees of Soviet repressive structures.

MGB agent under the codename Platonas successfully pretended to be captain in the Lithuanian army, after which he set up a meeting with the leadership in the forest of Kaziškė.