Glover, who stars in forthcoming spin-off Solo: A Star Wars story, made the quip during a sketch as he hosted US comedy variety show Saturday Night Live.
It came as the actor and musician – who is also known as Childish Gambino – prompted controversy with his new music video which comments on gun violence in America.
In the video, he is seen shooting a choir of black singers who fall to the ground, before he resumes dancing and smiling.
In his television sketch, he appeared as his character Lando Calrissian hosting a “galactic summit for black humans”.
Glover joked that “this started with one question – where the hell are all the black people in space?”
He said: “For a while I thought it was me, the only one, but now I see before me all the black humans in the galaxy.”
The camera cut away to a large function room with just three people sat in it.
Glover continued: “I’ll say it – turnout was a little low. We were expecting a thousand guests – I held out a hope that there was a black human planet somewhere, but I guess it’s just us.
“Lots of lizard men wearing vests. Just four black people though.”
There have been far fewer black main characters than white throughout the franchise’s history, including Lando Calrissian, Mace Windu (Samuel L Jackson), Finn (John Boyega) and Saw Gerrera (Forest Whitaker).
Thandie Newton appears in the new Han Solo standalone film as Val.
During his hosting stint on Saturday Night Live, Glover debuted his new single and video This Is America.
The video sees him dance through a warehouse in between graphically shooting a black guitarist and a 10-strong choir.
More from Entertainment
Porn star Stormy Daniels demands Trump resignation during cameo in Saturday Night Live comedy sketch
Avengers: Infinity War set to hit $1bn at the box office in record time
Trump says ‘thank you Kanye!’ as his African-American approval rating doubles
Kanye West reveals ambitions to become ‘biggest real estate developer’ ever
Star Wars Day: Heathrow celebrates with fake flights to Alderaan and Death Star on departures board
Bill Cosby and Roman Polanski kicked out of Oscars film academy
At points he is joined by a group of dancing black children in school uniforms as they perform in the middle of a riot-like scene, complete with police cars with flashing sirens.
This Is America has since become the number one trending video on YouTube with more than five million views.