Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

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

AQR Global Equity Fund N (AQGNX): 1.08% expense ratio and 0.6% management fee. AQGNX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations AQGNX has achieved five-year annual returns of an astounding 14.34%.

Vaughan Nelson Emerging Mkts Instl (ADVMX Quick QuoteADVMX - Free Report) : 1.01% expense ratio and 0.85% management fee. ADVMX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. ADVMX, with annual returns of 10.26% over the last five years, is a well-diversified fund with a long track record of success.

BlackRock Impact US Equity Instl (BIRIX) is an attractive large-cap allocation. BIRIX is classified as a Large Cap Blend fund. More often than not, Large Cap Blend mutual funds invest in companies with a market cap of over $10 billion. Buying stakes in bigger companies offer these funds more stability, and are well-suited for investors with a "buy and hold" mindset. BIRIX has an expense ratio of 0.48%, management fee of 0.4%, and annual returns of 12.6% over the past five years.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.