Some investments are better than others for a Roth IRA. Generally, stocks, stock mutual funds, or stock ETFs are good choices because they offer the potential for growth over time. However, it's important to remember that there is always some risk associated with investing in the stock market, so you may lose some of your money if the market declines. Bonds, bond mutual funds, or bond ETF's are also a good option for a Roth IRA, since they tend to provide stability and modest growth potential. You should avoid high-yield or risky investments, such as penny stocks, when investing in a Roth IRA.