Lech Wałęsa (born 29 September 1943) is a Polish statesman, dissident and Nobel Peace Prize laureate who served as the president of Poland between 1990 and 1995. After winning the 1990 election, Wałęsa became the first democratically elected president of Poland since 1922 and the first-ever Polish president elected by popular vote. An electrician by trade, Wałęsa became the leader of the opposition Solidarity movement and led a successful pro-democratic effort, which in 1989 ended Communist rule in Poland and ushered in the end of the Cold War.

While working at the Lenin Shipyard (now Gdańsk Shipyard), Wałęsa, an electrician, became a trade-union activist, for which he was persecuted by the government, placed under surveillance, fired in 1976 and arrested several times. In August 1980, he was instrumental in political negotiations that led to the ground-breaking Gdańsk Agreement between striking workers and the government. He co-founded the Solidarity trade union, whose membership rose to more than ten million.

After martial law in Poland was imposed and Solidarity was outlawed, Wałęsa was arrested again. Released from custody, he continued his activism and was prominent in the establishment of the Round Table Agreement that led to the semi-free 1989 Polish parliamentary election and a Solidarity-led government. He presided over Poland's transition from Marxist–Leninist state socialism into a market-based liberal democracy, but his active role in Polish politics diminished after he narrowly lost the 1995 Polish presidential election. In 1995, he established the Lech Wałęsa Institute.

Since 1980, Wałęsa has received hundreds of prizes, honors and awards from multiple countries and organisations worldwide. He was named the Time Man of the Year (1981) and one of Time's 100 most important people of the 20th century (1999). In 1983, he was awarded the Nobel Peace Prize, which was received by his wife, as he worried the authorities would not let him return. He has received more than forty honorary degrees, including from Harvard University, Fordham University and Columbia University, as well as dozens of high state orders, including being awarded the Presidential Medal of Freedom, and being appointed a Knight Grand Cross of the Order of the Bath, and a Grand Cross of the Legion of Honour. In 1989, Wałęsa was the first foreign non-head of state to address the Joint Meeting of the U.S. Congress. The Gdańsk Lech Wałęsa Airport has borne his name since 2004.

Lech Wałęsa was born in Popowo, Lipno county in the present-day Kuyavian-Pomeranian voivodeship, then under Nazi German occupation. His father, Bolesław Wałęsa (1909–1945), was a carpenter who was rounded up and interned in a forced labour camp at Młyniec (outpost of KL Stutthof) by the German occupying forces before Lech was born. Bolesław returned home after the war but died two months later from exhaustion and illness. Lech's mother, Feliksa Wałęsa (née Kamieńska; 1915–1976), has been credited with shaping her son's beliefs and tenacity. After Bolesław's death, Feliksa remarried her brother-in-law, Stanisław Wałęsa (1917–1981), a farmer. Lech had three elder full siblings; Izabela (1935–2012), Edward (born 1937) and Stanisław (born 1940); and three younger half-brothers; Tadeusz (born 1945), Zygmunt (born 1948) and Wojciech (1950–1988). In 1973, Lech's mother and stepfather emigrated to the US for economic reasons. They lived in Jersey City, New Jersey, where Feliksa died in a car accident in 1976 and Stanisław died of a heart attack in 1981. Both of them were buried in Poland.

In 1961, Lech graduated from primary and vocational school in nearby Chalin and Lipno as a qualified electrician. He worked as a car mechanic from 1962 to 1964, and then embarked on his two-year, obligatory military service, attaining the rank of corporal before beginning work on 12 July 1967 as an electrician at Lenin Shipyard (Stocznia Gdańska im. Lenina), now called Gdańsk Shipyard (Stocznia Gdańska) in Gdańsk.

From early in his career, Wałęsa was interested in workers' concerns; in 1968 he encouraged shipyard colleagues to boycott official rallies that condemned recent student strikes. He was a charismatic leader, who helped organise the illegal 1970 protests at the Gdańsk Shipyard when workers protested at the government's decree raising food prices and he was considered for the position of chairman of the strike committee. The strikes' outcome, which involved the deaths of more than 30 workers, galvanised Wałęsa's views on the need for change. In June 1976, Wałęsa lost his job at the Gdańsk Shipyard because of his continued involvement in illegal unions, strikes, and a campaign to commemorate the victims of the 1970 protests. Afterwards, he worked as an electrician for several other companies but his activism led to him continually being laid off and he was jobless for long periods. Wałęsa and his family were under constant surveillance by the Polish secret police; his home and workplace were always bugged. Over the next few years, he was arrested several times for participating in dissident activities.

Wałęsa worked closely with the Workers' Defence Committee (KOR), a group that emerged to lend aid to people arrested after the 1976 labor strikes and to their families. In June 1978, he became an activist of the underground Free Trade Unions of the Coast (Wolne Związki Zawodowe Wybrzeża). On 14 August 1980, another rise in food prices led to a strike at the Lenin Shipyard in Gdańsk, of which Wałęsa was one of the instigators. Wałęsa climbed over the shipyard fence and quickly became one of the strike leaders. The strike inspired other similar strikes in Gdańsk, which then spread across Poland. Wałęsa headed the Inter-Enterprise Strike Committee, coordinating the workers at Gdańsk and at 20 other plants in the region. On 31 August, the government, represented by Mieczysław Jagielski, signed an accord (the Gdańsk Agreement) with the Strike Coordinating Committee. Wałęsa used an oversized pen to sign the agreement, which was shown on television networks worldwide. The agreement granted the Lenin Shipyard workers the right to strike and permitted them to form an independent trade union. The Strike Coordinating Committee legalised itself as the National Coordinating Committee of the Solidarność (Solidarity) Free Trade Union, and Wałęsa was chosen as chairman of the committee. The Solidarity trade union quickly grew, ultimately claiming more than 10 million members – more than a quarter of Poland's population. Wałęsa's role in the strike, in the negotiations, and in the newly formed independent trade union gained him fame on the international stage.