Seymour was awarded the Order of Merit, Third Class by President Volodymyr Zelensky for supporting the state sovereignty and territorial integrity, charitable activity, and promoting the Ukrainian state in the world.
The deputy prime minister was one of 143 individuals to receive an award on the honours list, including the presidents of Portugal, Finland, Croatia and the Netherlands.
Seymour said the award came "totally out of the blue".
"I just got a message from the Ukrainian ambassador over in Sydney, who I've met a few times, and he said 'here you go, the president has recognised you.'
"I note that he's recognized quite a number of people at the same time, but I think their cause is incredibly important and I've only done a few little things, tiny things, really, but it's nice that they recognise me."
Seymour, a long-time advocate for the end of the Ukraine war, has organised fundraisers and petitioned to give sanctuary to Ukrainian-Kiwi families, as well as calling for unused Defence Force Javelin Missiles to be sent over for the war effort.
"The Ukrainians are fighting for their own lives, but in many ways, all of our freedom, because if large powers can just redraw boundaries anywhere on the map, that's a big problem for countries like New Zealand, and the only way to protect ourselves is to stand beside people who come under similar challenges to ours," he said.
Seymour said the Ukrainian conflict was "very different from the situation in the Middle East" where people had been attacking each other "back and forward for generations and everybody's got an opinion".
"This is cut and dry. One country attacked another across an internationally recognized border. That cannot stand in our society and that's why New Zealand, I'm very proud, stands with Ukraine," he said.
It had been a difficult winter for Ukraine, Seymour said.
"I just can't tell you how much respect and admiration I have for people who have chosen to go and put themselves in harm ways, to stand up for a principle that we all benefit from," he said.
