The Vanguard MSCI Index International Shares ETF (ASX: VGS) is one of the most popular exchange-traded funds (ETFs) on the ASX. Particularly among funds that don't directly track ASX shares.

This index fund currently has around $9.45 in assets under management. As such, we know that more than a few Australian investors are entrusting the VGS ETF with their hard-earned cash.

At first glance, the appeal of this ETF is obvious. It is an easy way for ASX investors to gain exposure to more than 20 stock markets around the globe, all hailing from the world's advanced economies. VGS contains stocks ranging from the United States, Finland, Portugal, Singapore, Hong Kong and the United Kingdom.

Its largest holdings are world-dominating companies like Apple, Alphabet, NVIDIA, JPMorgan and Meta Platforms.

So this index fund has a lot to offer ASX investors, particularly those whose portfolios are mostly made up of blue chips like Commonwealth Bank of Australia (ASX: CBA), Telstra Group Ltd (ASX: TLS), and Woodside Energy Group Ltd (ASX: WDS).

However, it's no secret that ASX investors love their dividend income and often prefer investing in ASX dividend shares for this reason, particularly if those shares attach full franking credits to their dividends.

With that in mind, let's discuss what kind of dividends one can expect from investing in the VGS ETF on the ASX.

Does the VGS ETF pay decent dividends to ASX investors?

The ASX's VGS ETF holds more than a thousand underlying holdings, many of which are dividend-paying shares. As such, it will come as no surprise that this ETF also pays its investors dividend income.

Like all ETFs, VGS is obliged to pass on any dividend income it receives from its underlying holdings to its investors. VGS does so in quarterly dividend distributions, which investors enjoy every three months.

However, since this fund's dividend income can vary wildly depending on what kind of income it receives from its many holdings, so do its own payments.

To illustrate, VGS investors have received a total of $4.02 per unit in dividend distributions. However, in the 12 months preceding that, investors bagged a total of $2.32.

Over the 12 months to November 2022, the total came in at $1.74 per unit, which was similar to the prior year's $1.87 per unit.

Foolish takeaway

So ASX investors can indeed count on VGS to pay out dividend income. However, that income is inherently unreliable in its magnitude. At least compared to many ASX shares. That's thanks to the diversified nature of this ETF's underlying portfolio.

If you are looking for an income share that will send you the same paycheque every three or six months, this fund is probably not the best fit for your portfolio.

The Vanguard International Shares ETF is probably a better fit for investors looking to add some growth-orientated international diversification to their existing ASX portfolios. Or who don't solely invest for dividend income.