Vējonis - the first member of a green political party in Europe to become a head of state - told delegates the world was at a defining moment as far as climate change was concerned.
"We truly are! The world is counting on us to make the Paris Agreement a reality!" Vējonis declared, according to the official text of his speech.
"Let us all respect and not re-interpret the Paris Agreement. Let’s make the long-term goals of the Paris Agreement a reality both here in COP 24 negotiations and back at home – in our daily activities and decisions!" he added.
He also joined the leaders of other countries in posing with a "thumbs up" gesture.
You can read his full address at the official presidential website.