This Presidential Primary coincides with a state/local primary. These coinciding primaries tend to have an impact upon voter turnout.

Tuesday 1 March 2016 (presumably): Texas Primary. Hours 7:00a-7:00p CST (1300-0100 UTC) / 7:00a-7:00p MST (1400-0200 UTC). Only the area around El Paso is in MST, so the vast majority of polls have closed in TX by 7 PM CST. Delegate Selection: Winner-Take-Most Primary. Voter Eligibility: Open Primary.

Primary
Source: Texas Secretary of State.
Status: Official. Retrieved: Thursday 21 April 2016.
Included in Nationwide vote.

Tuesday 1 March 2016 (presumably): All 155 of Texas's delegates to the Republican National Convention are bound to presidential contenders in today's Texas Presidential Primary. [General Rules for All Conventions and Meetings. Rule 38.]

• 108 district delegates are to be allocated to presidential contenders based on the primary results in each of the 36 congressional districts: each congressional district is assigned 3 National Convention delegates. These delegates are allocated to the presidential contenders as follows:
• If a candidate receives a majority of the vote (more than 50%), that candidate is allocated all 3 of the district's delegates. [General Rules for All Conventions and Meetings. Rule 38. Section 8.a. and 8.b.]
• If no candidate receives a majority of the vote and at least 1 candidate receives 20% or more of the vote, the candidate with the most votes (plurality) receives 2 delegates and the candidate receiving the next highest number of votes receives 1 delegate. [Rule 38. Section 8.b.]
• If no candidate receives 20% of the vote then the top 3 vote getters each receive 1 delegate. [Rule 38. Section 8.c.]
• 47 at-large delegates (10 base at-large delegates plus 34 bonus delegates plus 3 RNC delegates) are to be allocated to the presidential contenders based on the primary results statewide. These delegates are allocated to the presidential contenders as follows:
• If a candidate receives a majority of the vote (more than 50%) that candidate is allocated all 47 at-large delegates. [Rule 38. Section 9.a. and 9.b.]
• If no candidate receives a majority of the vote and at least 2 candidates receive 20% or more of the vote, the 47 at-large delegates are allocated proportionally among those candidates receiving 20% or more of the vote. Rounding rules: Beginning with the candidate receiving the largest number of votes, round any fraction to the next whole number of delegates. Continue this process with the next highest vote getter and repeat until all the delegates are allocated. [Rule 38. Section 9.b.]
• If no candidate receives a majority of the vote and only 1 candidate receives 20% or more of the vote, the 47 at-large delegates are allocated proportionally between the candidate receiving 20% or more of the vote and the candidate receiving the next highest number of votes. Rounding rules: Beginning with the candidate receiving the largest number of votes, round any fraction to the next whole number of delegates. Continue this process with the next highest vote getter and repeat until all the delegates are allocated. [Rule 38. Section 9.b.]
• If no candidate receives 20% of the vote, allocate the 47 at-large delegates proportionally. Rounding rules: Beginning with the candidate receiving the largest number of votes, round any fraction to the next whole number of delegates. Continue this process with the next highest vote getter and repeat until all the delegates are allocated. [Rule 38. Section 9.c.]

Primary
Source: Texas Secretary of State.
Status: Official. Retrieved: Thursday 21 April 2016.

Statewide proportional of candidates 20% or more.
Cruz: 47 × 1,240,777 ÷ 1,999,325 = 29.168 rounds up to 30 delegates.
Trump: 47 × 758,548 ÷ 1,999,325 = 17.832 truncates to 17 delegates.

In addition to the ballot listing of the names of the qualifying Presidential candidates, there shall appear at the bottom of such listing ... a place designated "Uncommitted" ... [Rule 38. Section 3.b]

A Presidential candidate may withdraw from participation in the Presidential Primary ... by filing with the Secretary of the SREC a signed and acknowledged request ... votes cast for that candidate shall be deemed votes for uncommitted [Rule 38. Section 2.d and 2.e]

Once the polls are closed, Precinct Conventions may be convened. While most Precinct Conventions occur on primary election day, they can occur at different dates including the Saturday following the primary, the Friday evening prior to or, the morning of the County and Senatorial District Conventions. The Precinct Conventions elect delegates to the County and Senatorial District Conventions.

Saturday 19 March 2016: County and Senatorial District Conventions. Delegates are elected to the State Convention.

Thursday 12 May - Saturday 14 May 2016 (presumably): The Texas Republican State Convention convenes in Dallas. The National Convention delegates are elected on the according to the results of the primary on the last day of the convention. [General Rules for All Conventions and Meetings. Rule 38.]

• 108 district delegates are elected: 3 from each of the state's 36 congressional districts.
• 44 at-large delegates (10 base at-large delegates plus 34 bonus delegates) are elected.
• The 3 party leaders, the National Committeeman, the National Committeewoman, and the chairman of the Texas's Republican Party, will attend the convention as pledged delegates by virtue of their position.

National Convention delegates are:

• bound for the 1st ballot unless "released from the pledge only in the event of death, withdrawal, or by decision of the candidate". [Section 10.b.1]
• bound for the 2nd ballot unless "released from the pledge if the candidate has failed to receive 20% or more of the total vote ... or by decision of the candidate.". [Section 10.b.2.]
• released for the 3rd and subsequent ballots. [Section 10.b.3]

10 February 2013: Texas state Senator Dan Patrick (Republican-Houston) has introduced SB 452. This bill would move the statewide and Presidential primaries from the 1st Tuesday in March to the 1st Tuesday in February and the run off from the 4th Tuesday in May to the 4th Tuesday in April.

26 February 2013: Texas state Representative Stephanie Klick (Republican) files HB 1911. The bill changes the general and presidential primary elections from the first Tuesday in March to the first Saturday in March. In addition, the runoff primary changes from the 4th Tuesday to the 4th Saturday in May.

Updated 17 March 2014 per the Republican Party of Texas rules as amended 7 December 2013.

12 November 2014: The Texas Republicans approved rule that will award 38 of their delegates based on a Presidential Preference vote taken at the state convention. Reference: Texas GOP wants bigger role in 2016 primaries - Star Telegram.

9 February 2015: HB 1214 is introduced by state Representative Lyle Larson (Republican). The bill change the date of the Presidential and partisan primaries from the 1st Tuesday in March to the 4th Tuesday in January.

The state Legislature adjourned on 1 June 2015 without passing any of these bills.