There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

The easiest way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

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

If you are looking to diversify your portfolio, consider Nuveen Core Equity R6 (TIGRX). TIGRX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks. This fund is a winner, boasting an expense ratio of 0.4%, management fee of 0.39%, and a five-year annualized return track record of 12.58%.

GMO International Oppotun Value III (GTMIX Quick QuoteGTMIX - Free Report) . Expense ratio: 0.69%. Management fee: 0.65%. GTMIX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. This fund has managed to produce a robust 14.8% over the last five years.

Invesco Value Opportunities R6 (VVOSX). Expense ratio: 0.65%. Management fee: 0.59%. Five year annual return: 17.68%. VVOSX 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.

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.