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, 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.

Goldman Sachs Flex Cap Growth I (GILLX Quick QuoteGILLX - Free Report) : 0.59% expense ratio and 0.55% management fee. GILLX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. With annual returns of 10.51% over the last five years, this fund is a winner.

JPMorgan US Equity I (JUESX Quick QuoteJUESX - Free Report) . Expense ratio: 0.69%. Management fee: 0.4%. JUESX is classified as a Large Cap Blend fund. More often than not, Large Cap Blend mutual funds invest in companies with a market cap of over $10 billion. Buying stakes in bigger companies offer these funds more stability, and are well-suited for investors with a "buy and hold" mindset. This fund has managed to produce a robust 10.76% over the last five years.

Invesco Small Cap Value A (VSCAX Quick QuoteVSCAX - Free Report) : 1.09% expense ratio and 0.64% management fee. VSCAX is a Small Cap Value mutual fund option, which typically invest in companies with market caps under $2 billion. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 11.71% 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.