- Random digit dialing
- Random sampling
- Ranking Minority Member
- Reapportionment
- Receipts
- Recess
- Recess appointment
- Recess Appointments Clause
- Recession
- Recognize
- Recommendations Clause
- Reconciliation Bill
- Reconciliation Instruction
- Reconciliation Process
- Reconsider
- Recorded Vote
- Redistricting
- Reexamination Clause
- Referral
- Regressive tax
- Regular Meeting Day
- Relevant
- Report
- Rescission
- Reserved powers
- Revenue sharing
- Reverse discrimination
- Revolving door
- Riddick's Senate Procedure
- Rider
- Right-of-rebuttal rule
- Right-to-Counsel Clause
- Roll Call Vote
- Rule making
- Rules Committee
- Rule of four