An Individual Retirement Arrangement (or IRA) is a retirement plan account that provides some tax advantages for retirement savings.

There are a number of different types of IRAs, which may be either employer-provided or self-provided plans. The types include:

• Roth IRA - contributions are made with after-tax assets, all transactions within the IRA have no tax impact, and withdrawals are usually tax-free. Named for Senator William Roth.
• Traditional IRA - contributions are often tax-deductible (often simplified as "money is deposited before tax" or "contributions are made with pre-tax assets"), all transactions and earnings within the IRA have no tax impact, and withdrawals at retirement are taxed as income (except for those portions of the withdrawal corresponding to contributions that were not deducted). Depending upon the nature of the contribution, a traditional IRA may be referred to as a "deductible IRA" or a "non-deductible IRA."
• SEP IRA - a provision that allows an employer (typically a small business or self-employed individual) to make retirement plan contributions into a Traditional IRA established in the employee's name, instead of to a pension fund account in the company's name.
• SIMPLE IRA - a simplified employee pension plan that allows both employer and employee contributions, similar to a 401(k) plan, but with lower contribution limits and simpler (and thus less costly) administration. Although it is termed an IRA, it is treated separately.
• Self-Directed IRA - a self-directed IRA that permits the account holder to make investments on behalf of the retirement plan.

There are two other subtypes of IRA, named Rollover IRA and Conduit IRA, that are viewed as obsolete under current tax law (their functions have been subsumed by the Traditional IRA) by some; but this tax law is set to expire unless extended. However, some individuals still maintain these accounts in order to keep track of the source of these assets. One key reason is that some qualified plans will accept rollovers from IRAs only if they are conduit/rollover IRAs.

What was formerly known as an Educational IRA is now called a Coverdell Education Savings Account. Starting with the Economic Growth and Tax Relief Reconciliation Act of 2001 (EGTRRA), many of the restrictions of what type of funds could be rolled into an IRA and what type of plans IRA funds could be rolled into were significantly relaxed. Additional acts have further relaxed similar restrictions. Essentially most retirement plans can be rolled into an IRA after meeting certain criteria, and most retirement plans can accept funds from an IRA. An example of an exception is a non-governmental 457 plan which cannot be rolled into anything but another non-governmental 457 plan.

The tax treatment of the above types of IRAs except for Roth IRAs are substantially similar, particularly for rules regarding distributions. SEP IRAs and SIMPLE IRAs also have additional rules similar to those for qualified plans governing how contributions can and must be made and what employees are qualified to participate.