Rosemary Butler told the BBC's Sunday Politics Wales show that the Isle of Man and Jersey had introduced the change.
She wants youth councils and forums for young people to consider the change from the current age of 18.
In Scotland the SNP Government wants 16 and 17-year-olds to take part in the referendum on independence there.
"Some people are a bit afraid of it, and other people think - I've got a job at 16, I'm paying tax so I should be able to vote," Mrs Butler said.
She added that it is a very interesting debate and that she hoped more people will take part in it.
"They're (16-year-olds) certainly up to it, whether they've got the confidence to do it, that might be a different matter, but then that goes for the whole of the population.
"If we encourage everybody to vote, then we'd have a true mandate," she said.
Kay Swinburne, Conservative MEP for Wales said she would rather a "broader" look was taken at voting patterns, as at the moment 18-24 year-olds are at the "poorer end of the spectrum" when it comes to turning out to vote.
"What we need to do is encourage everyone to use their democratic right," she added.
Throughout Europe only Austria had lowered the voting age since 2007, she said.
North Wales Liberal Democrat AM, Aled Roberts, said his party was in favour of lowering the voting age.
"But we need to get people to understand that voting for the assembly is important... that a vote can make a difference," he added.
The assembly's presiding officer has called for a debate on lowering the voting age in Welsh elections to 16.