An island of 5.5 million people that sits just north of the equator, Singapore was a post-colonial backwater when it gained independence from Malaysia in 1965. It is now a global business hub, and one of the richest countries in the world.
The highlight of the day's celebration, a nearly three-hour long parade in the evening, showcased military vehicles, performances by the island nation's different ethnic groups, and an aerial show by 50 military aircraft. A 26,000 strong audience gathered at the central stage, along with millions watching on television.
It is the second time this year that Singaporeans have come together to reflect on the national success. The first was after the death of the first prime minister, Lee Kuan Yew, in late March.
"At 50 years, as we stand at a high base camp, we look back and marvel how far we have come ... " Prime Minister Lee Hsien Loong, the son of Lee Kuan Yew, said in a televised speech on the eve of the national day.
"From this base camp, we can also look forward to new peaks ahead. The journey ahead is uncharted. But we must press on, because we aspire to do better for ourselves and our children."
He spoke at the Victoria Concert Hall, where his father launched the People's Action Party in 1954. The party has ruled Singapore since independence.
Regional leaders attending the parade included Malaysian Prime Minister Najib Razak, China's Vice President Li Yuanchao and Australian Deputy Prime Minister Warren Truss.
The official logo for the celebration is a red dot, a symbol of pride and defiance since the 1990s, when an Indonesian leader reportedly called Singapore "a little red dot" on the map. The image, with "SG50" in white characters, is ubiquitous, adorning banners, buses, cakes and a host of goods in shops.
A recording of Lee Kuan Yew reading the Proclamation of Independence, the document that announced Singapore's separation from Malaysia, was played on radio and television channels at 9 a.m. (0100 GMT)
Prime Minister Lee is widely expected to call the next election as early as September. His party suffered its worst-ever showing in the last parliamentary election, in 2011, with voters discontent over a widening wealth gap, sky-rocketing property prices and an influx of foreign workers.
Political analysts expect Lee's party to win more votes this time, thanks in part to the after-glow of the anniversary celebrations and in part to government efforts to address issues irking the public.
Still, when the banners are taken down, Singapore will return to debates over how to keep the economy growing while combating a low birth rate, anger over prices and a backlash over many years of liberal immigration policies.