A Duma (Russian: Ду́ма, Russian pronunciation: [ˈdumə]) is any of various representative assemblies in modern Russia and Russian history. The State Duma in the Russian Empire and Russian Federation corresponds to the lower house of the parliament. Simply it is a form of Russian governmental institution, that was formed during the reign of the last Tsar, Nicholas II. It is also the term for a council to early Russian rulers (Boyar Duma), as well as for city councils in Imperial Russia ('Municipal dumas'), and city and regional legislative bodies in the Russian Federation.

The term comes from the Russian word думать (dumat’) meaning "to think" or "to consider", cognate with the English words "doom" and "deem" which connote a judgment or decision (usually negative). The Boyar Duma was an advisory council to the grand princes and czar of Russia. The Duma was discontinued by Peter the Great, who transferred its functions to the Governing Senate in 1721.

Since the year 1 the municipalities in European, Russia have had institutions like those of the zemstvos. All owners of houses, tax-paying merchants and workmen are enrolled on lists in a descending order according to their assessed wealth. The total valuation is then divided into three equal parts, representing three groups of electors very unequal in number, each of which elects an equal number of delegates to the municipal duma. The executive is in the hands of an elective mayor and an uprava, which consists of several members elected by the duma. Under Alexander III, however, by laws promulgated in 1892 and 1894, the municipal dumas were subordinated to the governors in the same way as the zemstvos. In 1894 municipal institutions, with still more restricted powers, were granted to several towns in Siberia, and in 1895 to some in Caucasia.

The State Duma (Russian: Госуда́рственная ду́ма (Gosudarstvennaya Duma), common abbreviation: Госду́ма (Gosduma)) in the Russian Federation is the lower house of the Federal Assembly of Russia (legislature), the upper house being the Federation Council of Russia. The Duma headquarters is located in central Moscow, a few steps from Manege Square. Its members are referred to as deputies. The State Duma replaced the Supreme Soviet as a result of the new constitution introduced by Boris Yeltsin in the aftermath of the Russian constitutional crisis of 1993, and approved by the Russian public in a referendum.

The State Duma was first introduced in 1906 and was Russia's first elected parliament. The first two attempts by Tsar Nicholas II were too radical and ineffective and were subsequently dissolved after only a few months each. After the 1907 electoral reform the third Duma, elected in November 1907, was largely made up of members of the upper classes, as radical influences in the Duma had almost entirely been removed. The establishment of the Duma after the 1905 Revolution was to herald significant changes to the Russian autocratic system. Furthermore the Duma was later to have a larger effect on Russia as it was one of the contributing factors in the February Revolution, which led to the abolition of the autocracy in Russia.