The support will help build resilience and help the country's government respond to urgent needs, including resettlement of displaced people. There are still more than 350,000 in camps set up after the quake.
It will also help improve co-ordination among donors in getting humanitarian support to those who need it.
International Development Secretary Justine Greening said: "Three years ago Haiti was struck by a devastating earthquake, the effects of which are still felt today. At the time the UK and the global community stepped up to help Haiti get back on its feet.
"But Haiti continues to be vulnerable to natural disasters, most recently Hurricane Sandy, which caused huge damage and suffering. Today, on this anniversary of the earthquake, the international effort must now be on enabling Haiti to better prepare for, withstand and recover from future shocks.
"The UK is committed to working with our international partners to ensure Haiti builds long-term resilience.
"This means boosting a country's ability to deal with disasters, whether it is helping people in earthquake zones build to withstand shocks or helping poor farmers to grow drought-resistant crops. Reducing the impact of natural disasters saves money, lives and livelihoods, especially in developing countries."
Helen Clark, head of the UN Development Programme, said: "We welcome the announcement of UK support for building resilience in Haiti. Earthquakes and hurricanes wipe out lives and livelihoods in an instant, so it's imperative that the international community not only responds to disasters after they happen but also ensures that at-risk countries like Haiti are better protected, prepared and able to help themselves when a crisis occurs."
The earthquake is thought to have killed 316,000 people. An additional 1.5 million were displaced to camps around the capital Port-au-Prince and other cities in the south.