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.

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

AB Large Cap Growth K (ALCKX Quick QuoteALCKX - Free Report) : 0.94% expense ratio and 0.48% management fee. ALCKX 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. ALCKX has achieved five-year annual returns of an astounding 10.68%.

Janus Henderson Global Life Science T (JAGLX Quick QuoteJAGLX - Free Report) : 0.91% expense ratio and 0.64% management fee. JAGLX is part of the Sector - Health category, offering investors a focus on the healthcare industry, one of the largest sectors in the American economy. JAGLX, with annual returns of 11.85% over the last five years, is a well-diversified fund with a long track record of success.

JPMorgan US Equity Fund R5 (JUSRX Quick QuoteJUSRX - Free Report) : 0.54% expense ratio and 0.4% management fee. JUSRX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset. With a five-year annual return of 10.44%, this fund is a well-diversified fund with a long track record of success.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.