The 20th Texas Legislature met from January 11 to April 4, 1887, in regular session, and from April 16 to May 15, 1888, in a called session. All members of the House of Representatives and a portion of the members of the Senate were elected in the 1886 general election.
| Affiliation | Members | Note |
|---|---|---|
| Democratic Party | 91 | |
| Republican Party | 2 | |
| People's Party | 1 | |
| Total | 94 |
^ Source material was unclear in which order the two Presidents pro tempore served.
Members of the Twentieth Texas Legislature as of the beginning of the Regular Session, January 11, 1887:
| District | Senator | Party | Took office |
|---|---|---|---|
| 1 | William L. Douglass | 1885 | |
| 2 | Caleb Jackson Garrison | Democrat | 1885 |
| 3 | William Henry Pope | Democrat | 1883 |
| 4 | William Thomas Armistead | Democrat | 1887 |
| 5 | Samuel D. Stinson | 1885 | |
| 6 | John Lafayette Camp, Jr. | 1885 | |
| 7 | Alexander White Gregg | 1887 | |
| 8 | William W. Davis | 1887 | |
| 9 | Leonard Anderson Abercrombie | Democrat | 1887 |
| 10 | John M. Claiborne | 1887 | |
| 11 | John Woods | Democrat | 1885 |
| 12 | Hermann Knittel | 1885 | |
| 13 | Jonathan Lane | Democrat | 1887 |
| 14 | Scott Field | 1887 | |
| 15 | Eldred James Simkins | 1887 | |
| 16 | J. O. Terrell | Democrat | 1885 |
| 17 | William Allen | 1887 | |
| 18 | Elbridge G. Douglass | 1887 | |
| 19 | Temple Lea Houston | Democrat | 1885 |
| 20 | James Jones Jarvis | Democrat | 1887 |
| 21 | Samuel C. Upshaw | 1887 | |
| 22 | Richard H. Harrison | 1885 | |
| 23 | Charles Keith Bell | 1885 | |
| 24 | George Washington Glasscock, Jr. | Democrat | 1885 |
| 25 | William Henry Burges | Democrat | 1887 (Prior: 1881–1883) |
| 26 | William H. Woodward | 1887 | |
| 27 | Francis E. MacManus | 1887 | |
| 28 | Robert Hance Burney | 1887 | |
| 29 | James Henry Calhoun | 1885 | |
| 30 | Louis N. Frank | 1887 | |
| 31 | Henry D. McDonald | 1887 |
^ Source material was unclear in which order the representatives served or if they served concurrently.
| District | Outgoing Senator | Reason for Vacancy | Successor | Date of Successor's Installation |
|---|---|---|---|---|
| District 22 | Richard H. Harrison | Harrison resigned April 20, 1887. | Waller Saunders Baker | April 16, 1888 |
| District | Outgoing Representative | Reason for Vacancy | Successor | Date of Successor's Installation |
|---|---|---|---|---|
| District 45 | John Humphreys | Representative Humphreys resigned after end of regular session (April 4, 1887). | Joel W. Booth | April 16, 1888 |
| District 46 | James Jarrott | Representative Jarrott resigned between sessions. | None | |
| District 64 | Benjamin Rush Plumley | Representative Plumley died on December 9, 1887. | Guy Morrison Bryan | May 2, 1888 |
| District 81 | John H. Clark | Representative Clark resigned on June 4, 1888. | None | |
| District 86 | David Robinson | Representative Robinson resigned after end of First called session (May 15, 1888). | None |