Mariam Dadiani (Georgian: მარიამ დადიანი; 1783 – 19 March 1841) was the last Queen Consort of the western Georgian kingdom of Imereti as the wife of King Solomon II. She was a daughter of Katsia II Dadiani, Prince of Mingrelia. After the Russian conquest of Imereti and Solomon's flight to the Ottoman Empire in 1810, Mariam fell in the hands of the Russian authorities who sent her in exile to Russia proper, where she was known as Maria Katsiyevna Imeretinskaya (Russian: Мария Кациевна Имеретинская).
Mariam was born in 1783, in the family of the Mingrelian ruling prince Katsia II, of the Dadiani dynasty, and his wife Elisabed, daughter of Teimuraz II of Kakheti. She was given in marriage, in the 1790s, to the Imeretian king Solomon II, who later fought his brother-in-law and Katsia's successor, Grigol Dadiani, over territorial disputes. The marriage proved to be childless. Therefore, Solomon had to designate his closest legitimate relative and a son of an old adversary, Prince Constantine, as heir apparent in 1804.
Solomon's reign was under threat from the Russian Empire, whose suzerainty he had accepted in 1804. He offered armed resistance to the Russian troops sent in to reinforce the tsar's decision to depose Solomon in February 1810. Mariam stood by her husband's side. Solomon was forced to capitulate in March 1810, but he escaped from captivity and reignited an anti-Russian rebellion in May 1810. The Russian commander-in-chief Alexander Tormasov retaliated by ordering General Simonovich to incarcerate Mariam, her sister Maria, wife of Prince Davit Mikeladze, and Solomon's sister Mariam, wife of Prince Malkhaz Andronikashvili, at the fortress of Poti. The arrested noblewomen were to receive food from their own estates; giving money to them was prohibited. Simonovich advised caution, warning that harsh treatment of the female dignitaries would exasperate the Imeretians.