Most performers arrived for the show wearing a white rose to symbolize their support for the movements, which tackle harassment and inequality.
Kesha also gave a powerful, stirring performance of her single Praying, which addresses her own experience of surviving abuse.
The singer was backed by an all-star choir, including Cyndi Lauper and Camila Cabello, who were dressed in white to reflect the white rose campaign.
The night’s other pivotal moment was a tribute to the music-loving victims of the tragedies in Manchester and Las Vegas.
Handwritten notes bearing the names of the dead were projected on the stage as country music stars Maren Morris, Eric Church and Brothers Osborne performed Eric Clapton’s Tears In Heaven.
All three acts played at the Route 91 festival last October before a gunman opened fire on the audience, killing 58.
By the end, Bruno Mars took a total of six trophies, including the three biggest prizes: Album of the year, song of the year and record of the year.
Speaking onstage, Bruno Mars paid tribute to his fellow nominees, saying: “You guys are the reason why I’m in the studio pulling my hair out.”
As well as the star’s own prizes, his recording engineers won a further award for their work on the album.
Bruno Mars’ victory robbed Kendrick Lamar’s more urgent, political album of the night’s main prizes – but the Compton-born star still took home five trophies, including best rap album, best rap song and best rap performance.
Kendrick Lamar’s victories came at the expense of rap veteran Jay-Z and his soul-baring album 4:44.
Jay-Z won none of his eight nominations and chose not to perform at the three-hour show. However, Kendrick Lamar tipped his hat to the elder star, declaring “Jay for president!” as he collected the best rap album award.
The night also saw performances from Lady Gaga, Sam Smith, Pink and Patti LuPone, who sang Evita’s Don’t Cry For Me Argentina as part of a tribute to Andrew Lloyd Webber.
Ed Sheeran, who could not attend the ceremony, won two prizes – best pop vocal performance for Shape Of You and best pop album for Divide.
There were also posthumous awards for Leonard Cohen and actress Carrie Fisher, who won best spoken word album for the audio version of her memoirs, The Princess Diarist.
Best Fight Against the System: The Hamilton Mixtape – Immigrants (We Get the Job Done), Alessia Cara – Scars to Your Beautiful, John Legend – Surefire, Logic feat Damian Lemar Hudson – Black Spiderman, Big Sean – Light, Taboo feat. Shaliene Woodley – Stand up/ Stand N Rock #NoDapl
Best Direction: Dave Meyers and The Little Homies (for Kendrick Lamar – Humble)
Best Cinematography: Kendrick Lamar – Humble
Best Art Direction: Kendrick Lamar – Humble
Best Choreography: Kanye West – Fade
Song of the Summer: Lil Uzi Ver – XO Tour L1if3
Best Visual Effects: Katy Perry feat. Skip Marley – Chained to the Rhythm
Kendrick Lamar was the biggest winner at this year’s MTV Video Music Awards (VMAs), taking home six prizes and opening the show with a message about police brutality.
Fellow rapper Cardi B also touched on the issue when she gave a shout-out to NFL player Colin Kaepernick who has been side-lined after protesting against racial injustice by kneeling during the national anthem before games.
“As long as you kneel with us, we’re gonna be standing for you,” she said.
Taylor Swift failed to appear at the event, but debuted her comeback music video for Look What You Made Me Do.
Her video has been watched more than 12 million times on YouTube already.
Earlier this year MTV announced it was abandoning traditional male and female categories, switching to gender-neutral awards instead.
Susan Bro handed out the Fight Against the System Award, just 15 days after Heather Heyer was killed during a protest against a far-right march in Charlottesville, Virginia.
Paying tribute to her daughter, she said: “I miss her, but I know she’s here tonight.”
Susan Bro was introduced by the stage by Reverend Robert Wright Lee IV, a descendant of the controversial general on the Confederate side of the US Civil War.
“We have made my ancestor an idol of white supremacy, racism, and hate,” he said.
All six nominees for the award shared the prize. Somali nominee K’naan, whose cover of a Hamilton track paid tribute to the work of immigrants, wore a mock Make America Great Again written in Arabic.
Michael Jackson’s daughter Paris also spoke out against the violence in Charlottesville, calling out “Nazi white supremacist jerks”.
“We as a nation with liberty as our slogan – we have zero tolerance for their violence, their hatred and their discrimination. We must resist.”
Artists mostly avoided referring to President Trump directly, but criticized his policies and events indirectly.
Host Katy Perry, who campaigned for Hillary Clinton in the 2016 election mocked Donald Trump with the new award: “Listen, guys, this is one election where the popular vote actually matters…so vote online, but hurry up, before some random Russian pop star wins!”
Musician Logic performed a powerful rendition of his song 1-800-273-8255 (named after the US suicide prevention hotline) with the lyrics: “I want you to be alive / You don’t gotta die today.”
He shared the stage with survivors of suicide attempts wearing “You are not alone” t-shirts.
Thirty Seconds to Mars frontman Jared Leto paid tribute to vocalists Chester Bennington and Chris Cornell who both took their own lives earlier this year.
Taylor Swift has become the first female singer to win album of the year award at the Grammys twice.
Her 1989 album won the award at this year’s Grammys in Los Angeles.
Kendrick Lamar won the most prizes on the night with five awards.
Taylor Swift also won best pop vocal album and best music video for her track Bad Blood.
Ed Sheeran also won his first two Grammys for song of the year and best pop solo performance for his number one hit Thinking Out Loud.
Photo Instagram Taylor Swift
A surprised Ed Sheeran beat Kendrick Lamar, Taylor Swift, country group Little Big Town and Wiz Khalifa to the song of the year accolade.
Taylor Swift was equally surprised at winning the top honor. Her album, which was released in 2014, came out too late to be eligible for last year’s awards so was finally recognized at this year’s ceremony.
The singer gave a powerful acceptance speech saying: “As the first woman to win album of the year at the Grammys twice, I want to say to young women: There are going to be people along the way who will try to undercut your success or take credit for your accomplishments or your fame.
“But if you focus on your work and don’t let those people sidetrack you, someday when you get where you’re going, you’ll look around and you’ll know it was you and the people that love you that put you there. And that will be the greatest feeling in the world.”
Kendrick Lamar’s wins included best rap album for To Pimp A Butterfly; best rap song and rap performance for Alright; best rap/sung collaboration and best music video, which he shared with Taylor Swift for Bad Blood.
Alabama Shakes were triple winners. They collected best alternative music album while their song Don’t Wanna Fight won best rock song and rock performance.
The Weeknd also picked up two Grammys for best urban contemporary album and best R&B performance.
Mark Ronson and Bruno Mars won two awards for their hit Uptown Funk, including record of the year, while Meghan Trainor was named best new artist.
Muse also won best rock album for Drones, and Tony Bennett collected his 18th Grammy for best traditional pop vocal album.
Justin Bieber also won his first Grammy for his collaboration with Skrillex and Diplo, winning best dance recording for Where Are U Now.
Amy – Asif Kapadia’s documentary on the life of Amy Winehouse – won the Grammy for best music film.
Kendrick Lamar is leading the 2016 Grammy nominations with 11 nods in total.
The hip-hop star is up for album of the year for To Pimp A Butterfly.
Kendrick Lamar’s competition comes from Taylor Swift, whose pop smash 1989 is finally nominated, a year after its release.
It came out too late to be eligible for last year’s awards, a fate which has befallen Adele’s 25 this time around.
Taylor Swift ties with R&B star The Weeknd for second place, with seven nominations apiece.
Ed Sheeran is up for two of the major prizes – song of the year and record of the year – for his emotive ballad Thinking Out Loud.
The former award goes to the writers (in this case Ed Sheeran and Amy Wadge), while the record of the year category takes into account the performance and production of a hit song.
Other nominees for song of the year include The Weeknd’s breakthrough hit Can’t Feel My Face and Mark Ronson’s global smash Uptown Funk.
Taylor Swift is nominated for the tongue-in-cheek single Blank Space, as is Kendrick Lamar for Alright, the hope-filled centerpiece of his album.
Kendrick Lamar’s domination of the shortlist is “a testimony to his artistry,” said Neil Portnow, head of the Recording Academy.
“He’s someone that’s very serious about his art and about his craft, and has been working it for quite some time. And this is one of those instances where the work pays off.”
Kendrick Lamar’s other nominations include best rap album and best pop duo/group performance for Bad Blood – a remix of one of the tracks on Taylor Swift’s 1989.
The singer is also shortlisted twice for best rap song, including Kanye West’s All Day, which he co-wrote – along with 18 other credited performers, which could make an interesting moment on stage if West wins.
Among the most prestigious awards in music, the Grammys feature an exhaustive 83 categories in 30 genres, including the likes of best tropical Latin album and best jazz improvisation.
Outside the main categories, the late Amy Winehouse is up for her seventh Grammy thanks to Asif Kapadia’s revealing documentary on her life; while a deluxe reissue of The Rolling Stones’ Sticky Fingers is up for best box set.
Justin Bieber, who had been considered a contender for some of the main prizes, only gets one nomination, for best dance recording; while Rihanna also misses out, despite her Paul McCartney duet FourFiveSeconds being tipped as a nominee for song of the year.
The Grammy Awards ceremony will take place on February 15, 2016, at the Staples Center in Los Angeles.