It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term investors' portfolios.

Let's learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

Goldman Sachs Growth Opportunity R (GGORX Quick QuoteGGORX - Free Report) : 1.4% expense ratio and 0.92% management fee. GGORX is a Mid Cap Growth mutual fund. These mutual funds choose companies with a stock market valuation between $2 billion and $10 billion. GGORX has achieved five-year annual returns of an astounding 8.37%.

Hotchkis & Wiley Intnl Value I (HWNIX): 0.95% expense ratio and 0.8% management fee. HWNIX is a part of the Non US - Equity fund category, many of which will focus across all cap levels, and will typically allocate their investments between emerging and developed markets. With yearly returns of 18.3% over the last five years, HWNIX is an effectively diversified fund with a long reputation of solidly positive performance.

American Funds Growth Portfolio R6 (RGWGX). Expense ratio: 0.01%. Management fee: 0%. Five year annual return: 11.69%. RGWGX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.