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 take a look at some of our top-ranked mutual funds with the lowest fees.

If you are looking to diversify your portfolio, consider BlackRock Advantage Large Cap Value R (MRLVX). MRLVX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. This fund is a winner, boasting an expense ratio of 1.04%, management fee of 0.49%, and a five-year annualized return track record of 10.14%.

Brown Advisory WMC Strategic European Equity & Income I (BAFHX Quick QuoteBAFHX - Free Report) : 1.03% expense ratio and 0.9% management fee. BAFHX is a Europe - Equity mutual fund investing in stocks across the vast European continent. With yearly returns of 13.46% over the last five years, BAFHX is an effectively diversified fund with a long reputation of solidly positive performance.

CCT Thematic Equity Institutional (THMEX). Expense ratio: 0.65%. Management fee: 0.5%. Five year annual return: 10.09%. THMEX 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

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.