- "Order! We shall have order!"
- ―Vice Chair Mas Amedda
The Vice Chair of the Senate (sometimes referred to as Vice Chairperson or Vice Chancellor of the Republic, usually addressed as Lord Speaker) assisted the Chancellor of the Republic in the running of the Galactic Senate.
The Vice Chair's duties included:
- Formally opening and closing sessions of the Senate.
- Formally opening and closing Senate debates and discussions.
- Moderating Senate debates and discussions.
- Calling senators to attend Senate sessions.
- Enforcing the procedural rules of the Senate.
- Disciplining senators who break said procedures.
The Vice Chair apparently frequently (or always) was a member of the Office of the Chancellor (despite having his/her own Office of the Vice Chair) and was responsible for the maintenance of the Senate when the Chancellor could not attend in person. As such, the Vice Chair's role was essentially a hybridization of a Speaker of the House and a Vice Chancellorship. The Vice Chair abstained from decisions among the Senate, although expressed their opinion when decisions became tied. The Vice Chair served as long as she/he could maintain the confidence of the Senate, and could be removed/instated in Senate elections independent of elections for Chancellor. While the Senate was in session, the Vice Chair would wield the speaker's staff, a symbolic wooden staff topped with a figure of the ancient politician Sistros, to demonstrate that he held authority over the Senatorial debates.
In the waning years of the Republic, Senate factions opposed to the current Chancellor would nominate one of their own for Vice Chair. The Vice Chair would then be able to use his control over procedures to ensure that the Chancellor would be essentially unable to get any work done without the approval of the Vice Chair (and thus, the Chair's faction).
This was the case with Mas Amedda, who was elected to the position in 40 BBY by the Rim faction to control Chancellor Finis Valorum. Amedda continued in that position under Chancellor Palpatine until at least the inauguration of the Galactic Empire; it is unknown if a Vice Chair continued to serve until the Senate's dissolution in 0 BBY (although it would seem that the position, along with the office of Senior Aide, was replaced with that of the Grand Vizier at some point). In the New Republic Senate, the Chair of the Senate replaced the Vice Chair.
- Jedi Academy: Return of the Padawan (Non-canonical mention)
- Cloak of Deception
- Star Wars: Episode I The Phantom Menace (First appearance)
- Darth Plagueis
- Star Wars: Episode II Attack of the Clones
- Star Wars Episode II: Attack of the Clones junior novel
- Republic HoloNet News Core Edition 14:7:02
- Star Wars: The Clone Wars – "Sphere of Influence"
- Star Wars: The Clone Wars – "Duchess of Mandalore"
- Star Wars: The Clone Wars – "The Zillo Beast" (Appears in flashback(s))
- Star Wars: The Clone Wars – "The Zillo Beast Strikes Back"
- Star Wars: The Clone Wars – "Heroes on Both Sides"
- Star Wars: The Clone Wars – "Pursuit of Peace"
- Star Wars: The Clone Wars – "Senate Murders"
- Star Wars: The Clone Wars – "Friends and Enemies"
- Star Wars: The Clone Wars – "Crisis on Naboo"
- Star Wars: The Clone Wars – "The Lawless"
- Star Wars: The Clone Wars – "The Jedi Who Knew Too Much"
- Star Wars: The Clone Wars – "The Wrong Jedi"
- Star Wars: The Clone Wars – "Orders"
- Star Wars: The Clone Wars – "The Rise of Clovis"
- Star Wars: The Clone Wars – "Crisis at the Heart"
- Star Wars: The Clone Wars – "The Disappeared, Part I"
- Star Wars: Episode III Revenge of the Sith
- Star Wars Episode III: Revenge of the Sith junior novel