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 break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

GMO International Oppotun Value III (GTMIX Quick QuoteGTMIX - Free Report) has a 0.78% expense ratio and 0.65% management fee. GTMIX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. With yearly returns of 12.88% over the last five years, this fund clearly wins.

Heartland Value Fund Investor (HRTVX). Expense ratio: 1.06%. Management fee: 0.75%. HRTVX is a Small Cap Value fund, and these funds are known for investing in companies with market caps under $2 billion. This fund has managed to produce a robust 15.43% over the last five years.

Janus Henderson Research Institutional (JAGRX) is an attractive large-cap allocation. JAGRX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks. JAGRX has an expense ratio of 0.67%, management fee of 0.56%, and annual returns of 16.98% 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.