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 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.

BNY Mellon Natural Resources I (DLDRX Quick QuoteDLDRX - Free Report) : 0.9% expense ratio and 0.75% management fee. DLDRX is a Sector - Energy fund, which are comprised of various changing and hugely important industries throughout the massive global energy sector. With annual returns of 18.72% over the last five years, this fund is a winner.

Thornburg Better World Intl A (TBWAX Quick QuoteTBWAX - Free Report) : 1.46% expense ratio and 0.98% management fee. TBWAX 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 11.49% over the last five years, TBWAX is an effectively diversified fund with a long reputation of solidly positive performance.

Westwood Large Cap Value Fund I (WHGLX Quick QuoteWHGLX - Free Report) : 0.65% expense ratio and 0.5% management fee. WHGLX is a part of the Large Cap Value category, and invests in equities with a market capitalization of $10 billion or more, but whose share prices do not reflect their intrinsic value. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 10.7% over the last 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.