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.

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

abrdn Emerg Markets ex-China IS (GLLSX): 1% expense ratio and 0.75% management fee. GLLSX is a Global - Equity mutual fund investing in bigger markets like the U.S., Europe, and Japan; these kinds of funds aren't limited by geography. With annual returns of 14.45% over the last five years, this fund is a winner.

Destinations Equity Income I (DGEFX Quick QuoteDGEFX - Free Report) : 0.97% expense ratio and 0.8% management fee. DGEFX 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. With yearly returns of 10.02% over the last five years, DGEFX is an effectively diversified fund with a long reputation of solidly positive performance.

DWS Equity Sector Strategy A (SUPAX). Expense ratio: 0.73%. Management fee: 0.28%. Five year annual return: 11.77%. SUPAX is a part of the Allocation Balanced fund category; these funds like to invest in a variety of asset types, finding a balance between stocks, bonds, cash, and sometimes even precious metals and commodities; they are mostly categorized by their respective asset allocation.

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.