An opposition party in October challenged the government's decision to send 1,000 officers to address a deepening crisis in Haiti, where gang violence killed at least 5,000 people and forced around 200,000 people from their homes last year.
Kenya had hoped to have its officers in Haiti as soon as this month after the United Nations Security Council approved the mission in October, but a court issued a stay on the deployment shortly after.
High Court Judge Chacha Mwita said that under Kenyan law, the authorities could only deploy officers abroad if a "reciprocal arrangement" was in place with the host government.
"Any further action or steps taken by any state organ or state officer in furtherance of such a decision, contravenes the Constitution and the law and is therefore unconstitutional, illegal and invalid," Mwita said.
The government did not immediately comment on whether it would appeal the ruling.
Haiti first requested help in 2022 as gang violence surged but was unable to find a country willing to lead a security mission.
Many governments have been wary of supporting Prime Minister Ariel Henry's unelected administration and intervening in a nation where previous missions have been dogged by human rights abuses.
Kenya finally stepped forward last July, saying it was doing so in solidarity with a brother nation. The Bahamas then committed 150 people, and Jamaica and Antigua and Barbuda said they were willing to help.
The United Nations said this week that it had documented 4,789 people killed by gang violence in Haiti last year, an increase of 119% from 2022, and that another 3,000 were kidnapped.