Lotte and the Moonstone Secret () is a 2011 Estonian animated film directed by Heiki Ernits and Janno Põldma. It is the third installment in the Lotte film series.
The film's characters first appeared in Lotte's Journey South (), an Estonian animated TV series, containing 13 five-minute episodes. In 2006, the animated feature film Lotte from Gadgetville was released.