Celebrations were held in the capital, Hargeisa, on Saturday, with people holding rallies, waving flags from their vehicles and staging shows in various stadiums.
Somaliland, which is more tribally homogeneous than the rest of Somalia, has been striving for international recognition since it broke away in 991.
Ahmed Mahamoud Silany, the region’s president, told Al Jazeera on Friday that, despite Somalia’s calls to be united with the region, Somaliland is determined to retain its independence.
“We would like to remain friends with Somalia, we would like to cooperate with them.
“But as far as our independence is concerned. It is not I who has decided, it’s not my government who has decided.
“It the people of Somaliland, and the history of Somaliland, which has decided that Somaliland is going to be, and has always been a different country.”
The UN and the African Union have both rejected calls to recognise Somaliland.
‘Oasis of peace’
Having escaped decades of conflict in Somalia, Somaliland, which sits on the Gulf of Aden, employs its own security and police forces, justice system and currency.
It has a reputation for successfully maintaining law and order for its population of 3.5 million.
Al Jazeera’s Nazanine Moshiri, reporting from Hargeisa, said that while war has raged in Somalia for decades, Somaliland has managed to unite its people.
“In the last few years Somaliland has become known as an oasis of peace in the horn of Africa,” she said.
Because Somaliland is not recognised as a state, it is not eligible for international development loans.
“Without recognition, it cannot get the foreign investment it needs,” Moshiri said, adding that aid is instead sent to Somalia.