Marc Carter's plea to find a replacement sippy cup for son Ben was retweeted more than 12,000 times.
The 14-year-old has only drunk from the double-handled vessels, which are no longer produced, since the age of two.
Tommee Tippee said it will produce 500 cups after it searched factories worldwide and found the original mould.
The firm's attention was drawn to the family's plight when Mr Carter launched the Twitter appeal to find a replacement.
More on a dad's desperate search for a cup, and other stories
His original plea prompted offers of help from as far away as Australia.
Mr Carter, 42, said the response from well-wishers had been "incredible" and it was a "huge surprise" to be contacted by the manufacturer.
Mr Carter said: "For me it's massive. Some people think I'm exaggerating but without it he doesn't drink so personally I'm very relieved."
Tommee Tippee will send the cups on demand for free to the Carter family.
Mr Carter said: "I would not be happier if I won the lottery. We've moved down to the middle of nowhere and don't want much.
"Just knowing he has got these cups gives us peace of mind."
Northumberland-based Tommee Tippee does not normally keep the moulds but had been searching factories around the world in the hope of finding the original plans.
A spokesman said: "We are delighted to confirm that we are able to start production on a run of the original cup.
"This will ensure that Ben has a lifetime supply and that his family won't ever have to worry about finding another cup for Ben."
Mr Carter, from Devon, told the BBC his son has had his current blue cup for three years, but it is now falling apart and may only last a few more weeks.
He said: "This tiny blue cup dictates our life."
A dad's desperate search to replace his autistic son's beloved "little blue cup" has ended - after the manufacturer stepped in to make a lifetime's supply.