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, 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.

Neuberger Berman Guardian Trust (NBGTX Quick QuoteNBGTX - Free Report) : 1.03% expense ratio and 0.88% management fee. NBGTX is a Large Cap Value fund. These funds invest in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. NBGTX has achieved five-year annual returns of an astounding 11.08%.

BlackRock Exchange BlackRock (STSEX Quick QuoteSTSEX - Free Report) is a stand out amongst its peers. STSEX 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. With five-year annualized performance of 10.7%, expense ratio of 0.62% and management fee of 0.5%, this diversified fund is an attractive buy with a strong history of performance.

Wells Fargo Special Technology Admiral (WFTDX Quick QuoteWFTDX - Free Report) is an attractive large-cap allocation. WFTDX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. WFTDX has an expense ratio of 1.2%, management fee of 0.85%, and annual returns of 8.79% 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.