Lada and Lado are alleged Slavic deities. Lada was first mentioned around 1405-1412 in the sermons of Lucas of Wielki Koźmin, which warned against worshipping Lada and other gods during spring ceremonies and folk performances. They owe their popularity to Jan Długosz, who in one of his sources recognized Lada as a goddess and in another as a god of war, the Polish equivalent of the Roman god Mars, to Aleksandr Faminstyn, who recognized the word Lada in Russian songs as the goddess of marriage, and to scholar Boris Rybakov, who insisted on recognizing her historicity. However, the vast majority of religious scholars and Slavists reject the historicity of these deities, believing that they owe their divine status to a misunderstanding of the song refrains by medieval scribes.

Niya is a Lechitic god of the underworld of unknown sex, whose exact functions are unknown. Niya is mentioned together with other gods worshipped by Poles, such as Yesha, Łada, or Devana. Niya's cult may be demonstrated by the sayings "Go to Niye" and "Dwell in Nya" collected by Polish ethnographer Aleksander Brückner. In recent years, the confidence in the authenticity of Niya has increased in the scientific community.