He initially designed an eight-colour flag in 1978 for the city's gay freedom day, the precursor to the modern pride parade.
The rainbow flag has been raised in central San Francisco to honour him.
It is flying near Harvey Milk Plaza, named after America's first openly gay politician, a close friend of Baker before his assassination in 1978.
Baker's close friend Cleve Jones said on Twitter: "My dearest friend in the world is gone. Gilbert Baker gave the world the Rainbow Flag; he gave me forty years of love and friendship."
Screenwriter Dustin Lance Black, who wrote the screenplay for Milk, the biopic of the politician, tweeted: "Rainbows weep. Our world is far less colourful without you, my love. Gilbert Baker gave us the rainbow flag to unite us. Unite again."
California State Senator Scott Weiner said Baker's work had "helped define the modern LGBT movement".
'A people, a tribe'According to his website, Baker was born in Kansas in 1951 and served in the US army from 1970 to 1972, which stationed him in San Francisco in the early days of the gay liberation movement.
He was honourably discharged, taught himself to sew and began a flag-making career which would include creating designs and displays for several world leaders including the presidents of France, Venezuela and the Philippines.
Baker's original flag had eight colours, each representing a different aspect of humanity:
- Pink - sexuality
- Red - life
- Orange - healing
- Yellow- sunlight
- Green - nature
- Turquoise - art
- Indigo - harmony
- Violet - human spirit
Read more: The rise of the rainbow flag
--More at BBC.com
The first Rainbow Flag was designed in 1978 by Gilbert Baker, a San Francisco artist, who created the flag in response to a local activist's call for the need of a community symbol. (This was before the pink triangle was popularly used as a symbol of pride.) Using the five-striped "Flag of the Race" as his inspiration, Baker designed a flag with eight stripes: pink, red, orange, yellow, green, blue, indigo, and violet. According to Baker, those colours represented, respectively: sexuality, life, healing, sun, nature, art (or magic), harmony (or serenity), and spirit. Baker dyed and sewed the material for the first flag himself - in the true spirit of Betsy Ross.
In November 1978, San Francisco's gay community was stunned when the city's first openly gay supervisor, Harvey Milk, was assassinated, Wishing to demonstrate the gay community's strength and solidarity in the aftermath of this tragedy, the 1979 Pride Parade Committee decided to use Baker's flag. The committee eliminated the indigo stripe so they could divide the colours evenly along the parade route - three colours on one side of the street and three on the other. Soon the six colors were incorporated into a six-striped version that became popularized and that, today, is recognized by the International Congress of Flag Makers.
In San Francisco, the Rainbow Flag is everywhere: it can be seen hanging from apartment windows throughout the city (most notably in the Castro district), local bars frequently display the flag, and Rainbow Flag banners are hung from lampposts on Market Street (San Francisco's main avenue) throughout Pride Month. Visiting the city, one can not help but feel a tremendous sense of pride at seeing this powerful symbol displayed so prominently.
Although the Rainbow Flag was initially used as a symbol of pride only in San Francisco, it has received increased visibility in recent years. Today, it is a frequent sight in a number of other cities as well - New York, West Hollywood, and Amsterdam, among them. Even in the Twin Cities, the flag seems to be gaining in popularity. Indeed, the Rainbow Flag reminds us that ours is a diverse community - composed of people with a variety of individual tastes of which we should all be proud.
So now you know!