President Barack Obama wrote: "Rest in peace, Steve Jobs. From all of us at #Obama2012, thank you for the work you make possible every day-including ours."
"My heart weeps for all who worked with Steve and who loved him, especially my friend Laurene and their children," wrote Maria Shriver. "I'm so happy that I knew him and was so blessed by his friendship. He impacted all of our lives and changed the world. I'm going to turn off my Apple computer, iPhone and iPad tonight at 8pm and honor Steve with a moment of digital silence. Will you join me?
"Steve lived the California Dream every day of his life and he changed the world and inspired all of us," Arnold Schwarzenegger wrote.
"RIP Steve Jobs ... what an innovator," tweeted Leann Rimes. "This world will miss him."
Jane Lynch wrote, "We will miss you, Steve Jobs. Sent lovingly from my iPhone."
"Rest in peace, Steve Jobs," said Neil Patrick Harris. "Your genius will live on for generations to come..."
"Design is not just what it looks like and feels like," tweeted Ashton Kutcher. "Design is how it works. - Steve Jobs RIP"
"Thank you Steve Jobs for so many 'wow, that's really cool' moments," wrote Dane Cook. "You changed the world by believing in your dreams."
"I just finished my show and I heard the news about Steve Jobs," Ellen DeGeneres wrote. "He was an amazing man with an incredible vision. He changed the world."
"We lost a man of true vision today," wrote Jon Favreau. "Condolences to the whole Apple family."
Steve Jobs died on Wednesday after years of battling pancreatic cancer. He was 56.