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.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

AB Large Cap Growth Adivsor (APGYX Quick QuoteAPGYX - Free Report) : 0.56% expense ratio and 0.48% management fee. APGYX 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 annual returns of 16.91% over the last five years, this fund is a winner.

Janus Henderson Global Technology Institutional (JGLTX Quick QuoteJGLTX - Free Report) . Expense ratio: 0.73%. Management fee: 0.64%. JGLTX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. This fund has managed to produce a robust 19.49% over the last five years.

Neuberger Berman Genesis Investor (NBGNX Quick QuoteNBGNX - Free Report) . Expense ratio: 0.99%. Management fee: 0.92%. Five year annual return: 10.35%. NBGNX is a Small Cap Value mutual fund option, which typically invest in companies with market caps under $2 billion.

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.