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, 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.

DFA Selectively Hedged Global Equity I (DSHGX Quick QuoteDSHGX - Free Report) : 0.31% expense ratio and 0.24% management fee. DSHGX 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 12.08% over the last five years, this fund is a winner.

Principal Capital Appreciation R5 (PCAQX). Expense ratio: 0.68%. Management fee: 0.41%. PCAQX 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. This fund has managed to produce a robust 13.59% over the last five years.

LSV Emerging Markets Equity Inv (LVAZX): 1.2% expense ratio and 1% management fee. LVAZX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. With a five-year annual return of 15.56%, 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.