O'Bryan, Ronald 3-31-1984 Lethal Injection Harris Huntsville, TX 529 Remuneration  
 O'Connor, Lawrence 4-26-1964 Electrocuted Harris Huntsville, TX 452 Rape  
 Oglesby, Joseph 9-2-1945 Electrocuted Reeves Huntsville, TX 273 Rape  
 Ortiz, Pantaleon 12-12-1933 Electrocuted Refugio Huntsville, TX 115 Murder  
 Outlaw, Charlie 4-27-1934 Electrocuted Angelina Huntsville, TX 131 Murder  

Texas Department of Criminal Justice Home Page for executions after 1977.  
The Rope, The Chair, And The Needle by James W. Marquart, ©1994, University of Texas Press for those executions before 1977.
Without Sanctuary by James Allen and John Littlefield, © 2000, for early lynchings in Texas.