Presiding Officer Dame Rosemary Butler has questioned why people can join the armed forces, pay taxes and get married at 16 but not cast their ballot.
In the Scottish independence referendum, in September, 16 year olds were given the vote for the first time.
But the voting age for local council, assembly and general elections remains unchanged at 18.
"It seems to me that 16-year-olds can be asked to contribute to their country's wealth without being able to have a say in how that money is spent," Dame Rosemary said.
"Last week, the Westminster government announced that they would legislate to allow 16 year olds in Wales to vote in any future referendum on the devolution of tax-varying powers to Wales.
"Would it not therefore follow that they should be able to vote in all elections?"
"That's why today I am launching a national conversation with young people to find out what they think."
The consultation with 11 to 25 year olds is being launched on Thursday to coincide with the 25th anniversary of the UN Convention on the Rights of the Child.
Young people from schools across Wales took part in a youth debate in Cardiff Bay on Wednesday.
Dylan Williams, a 17-year-old sixth form pupil at Ysgol Gyfun Cwm Rhymni, near Caerphilly, told BBC Wales he did not "see in school the interest in politics" to justify lowering the voting age.
"Every time we have a lesson about politics everyone sighs - it's their least favourite topic," he said.
"There's just a lack of interest in the whole year."
But fellow pupil Megan Lewis, 16, said this was not an argument against allowing her to vote.
"Personally, I don't know much about politics but if I was given the vote I would do a lot of work to find out... what politicians I should be voting for," she said.
Young people will be able to complete an online survey at the 'Your Assembly - your say, your way' website.
Assembly teams will also visit youth groups as part of the six month consultation and produce information packs to help young people hold their own debates.
An assembly "youth day" in July will consider the results and what to do next.
Young people are to be asked whether 16 year olds should be allowed to vote in Welsh assembly elections.