Since 1867 there have been four successive currencies in Romania known as the leu (plural lei). This article details the banknotes denominated in the leu and its subdivision the ban since 1917, with images.

The leu notes issued on 1 July 2005 are of equal size to euro banknotes, so that machines will need less refitting once Romania joins the euro zone. This decision was taken after a lot of debate, and with some opposition, the initial decision being to make them even smaller, similar to the 1966 series. The old leu notes were rather long and fairly uncomfortable to carry.

The design of the notes follows some common guidelines: the obverse shows a flower native to Romania and the portrait of a Romanian cultural personality; the reverse shows a building or a well-known monument. All banknotes are printed on plastic polymer, each in its own colour theme (light green for 1 leu, light purple for 5 lei, light pink and light orange for 10 lei, yellow for 50 lei, blue for 100 lei, dark orange for 200 lei, and light gray for 500 lei). On 14 November 2008 the National Bank of Romania announced the issue of a redesigned 10 lei banknote. The new design employs offset printing in favor of the intaglio printing used in the 2005 series. Also the transparent window will undergo a shape redesign.^[2]

Each banknote also features a small transparent window, in the shape of a distinctive item characterising the activity of the pictured personality, a heraldic symbol for Nicolae Iorga, a music key for George Enescu, painting implements for Nicolae Grigorescu, an eagle for flying pioneer Aurel Vlaicu, theater masks for Ion Luca Caragiale, a pen point for Lucian Blaga and an hourglass symbolising poetry and time for Mihai Eminescu. Each banknote has a different texture, to be easily recognised in the pocket or by those with visual impairments.

Note that the 500 lei banknotes see limited usage since they are not dispensed by automated teller machines.

On 21 December 2017, the National Bank of Romania announced that beginning with 1 January 2018, all the banknotes and coins will feature the new version of the coat of arms. All other features (portraits, security etc.) remain unchanged.^[3] The banknotes will feature the date of issue 1 January 2018, and will be released as demanded. The 1 July 2005, 1 December 2006, and 1 December 2008 issues will continue to be legal tender and circulate in parallel with the revised banknotes.

On 31 July 2019, the National Bank of Romania announced that it planned to issue the 20 lei banknote, which will feature Ecaterina Teodoroiu, in 2020.^[4] In November 2021 the National Bank of Romania announced that the 20 lei banknote bearing Ecaterina Teodoroiu's portrait would be issued on 1 December 2021.^[5][6]