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 take a look at some of our top-ranked mutual funds with the lowest fees.

Fidelity International Growth (FIGFX Quick QuoteFIGFX - Free Report) : 0.92% expense ratio and 0.71% management fee. FIGFX is a Non US - Equity fund. Many of these funds like to allocate across emerging and developed markets, and will often focus on all cap levels. With annual returns of 9.8% over the last five years, this fund is a winner.

Principal Large Cap Growth I R5 (PPUPX Quick QuotePPUPX - Free Report) is a stand out amongst its peers. PPUPX 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. With five-year annualized performance of 14.25%, expense ratio of 0.85% and management fee of 0.6%, this diversified fund is an attractive buy with a strong history of performance.

Glenmede Small Cap Equity I (GTSCX Quick QuoteGTSCX - Free Report) : 0.75% expense ratio and 0.55% management fee. GTSCX is a Small Cap Value mutual fund option, which typically invest in companies with market caps under $2 billion. With a five-year annual return of 10.7%, this fund is a well-diversified fund with a long track record of success.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.