The Texas Democratic Party is the affiliate of the Democratic Party in the U.S. state of Texas and one of the two major political parties in the state. The party's headquarters are in Austin, Texas.

President Lyndon B. Johnson was a Texas Democrat. 39 out of the 48 politicians who have served as Governor of Texas have been Texas Democrats. The party used to be the dominant political party in Texas; however, like in other Southern states, its rival, the Republican Party of Texas has become the dominant party since the 1990s. Texas has not elected any Democratic candidates to statewide office since 1994. Texas has the longest streak of any state for not electing Democrats to any statewide office, and has not voted Democratic in a presidential election since 1976.

The party used to support racial segregation and held white-only primaries until Terry v. Adams; however, the party has adopted liberal attitudes on race and other matters since the 1960s.

Similar to the national Democratic Party, the Texas Democratic Party currently supports increasing educational funding, abortion access, cannabis legalization, LGBT rights, environmentalism, gun control, Medicaid expansion, and raising the minimum wage. Black Texans, Hispanic Texans, young Texans, and Texans who live in urban areas are more likely to support the Texas Democratic Party than other demographic groups. However, Hispanic Texans have shifted towards the Republican Party in recent elections.

Prior to the Annexation of Texas, the Democratic Party had a foothold in the politics of the region. A powerful group of men that called themselves the "Texas Association" served as an early prototype for the Democratic Party of Texas. The Texas Association drew its membership from successful merchants, doctors, and lawyers, often traveling from Tennessee. Many members of the Texas Association were close friends of Andrew Jackson, and most had strong ties to the Democratic Party. Similarly, most of the other settlers in Texas were from states in the South, and white American southerners of this era generally held strong allegiances to the Democratic Party.

In 1845, the 29th United States Congress approved the Texas Constitution and President James K. Polk signed the act admitting Texas as a state on December 29. In 1848, the party convention system was adopted, and it quickly became the primary method of selecting candidates for the Texas Democratic Party. In the period prior to the Civil War, national politics influenced the state party's perspective. Texas Democrats began to discard Jacksonian nationalism in favor of the states' rights agenda of the Deep South. A conflict emerged within the Party between a minority of pro-Union Democrats and a majority of secessionists. During the war, supporters of the Union disappeared from the political scene or moved north. Those who stayed politically active supported the Confederacy. During Reconstruction, the rift between Unionist and Secessionist Democrats remained. For a short period immediately after the war, the Texas Democratic Party was a formidable political force, but they quickly split apart because their positions on freedmen varied greatly; some supported basic civil rights, while most opposed anything more than emancipation. As a result, Republicans captured both the governor's office and the Texas Legislature in 1869, but Republican political dominance in the post-Civil War era was short-lived. By 1872, the Texas Democrats had consolidated their party and taken over the Texas legislature. For the remainder of the 19th century and well into the 20th, Democrats dominated Texas politics and Republicans were minor political players.

In the presidential election of 1928, anti-Catholicism in Texas and across the country swung Texas away from Democratic presidential nominee Al Smith, the first time it ever voted against a Democrat in a presidential election. However, it was not until the middle of the 20th century that the Democrats began to face a growing challenge from the Republican Party in earnest. The 1950s was a decade of factionalism and infighting for the Texas Democratic Party, mainly between liberal and conservative Democrats, and the Republicans managed to carry Texas for native Dwight D. Eisenhower in 1952 and 1956. Cohesion returned to the party in the 1960s, and the Democratic ticket carried Texas in the 1960 presidential election with prominent Texas Senator Lyndon B. Johnson running for Vice President. In 1962, John B. Connally, a moderate Democrat, was elected Governor of Texas. The next year, the assassination of President John F. Kennedy on a trip to Dallas created further impetus to bridge the gap between liberal and moderate Texas Democrats; Party unity was solidified with Johnson's ensuing Presidency and the drubbing of Barry Goldwater in the 1964 presidential election. In 1964, Johnson carried his home state with ease, but liberal forces in Texas were in decline. In the 1968 presidential election, Democrat Hubert Humphrey barely managed to win Texas.

In 1976, Jimmy Carter became the last Democratic presidential candidate to carry Texas, and the tide was clearly turning when Democrats lost the gubernatorial election of 1978. Bill Clements was the first Republican governor since Reconstruction. By the 1990s Republicans had gained a strong foothold in the state, and throughout the 21st century they have been largely victorious. Currently, both houses of the Texas Legislature feature Republican majorities.