"This administration has done everything it can to sideline & ignore Tesla," Musk wrote on Twitter.
The tweet came while Musk is in the midst of purchasing Twitter. The billionaire has said he plans to reinstate Trump after he was banned following the siege on the Capitol last year.
"In the past I voted Democrat, because they were (mostly) the kindness party," he added. "But they have become the party of division & hate, so I can no longer support them and will vote Republican. Now, watch their dirty tricks campaign against me unfold."
Before he announced his plans to switch political parties, Musk said Biden was only elected because people "wanted less drama." The billionaire has said he supports "centrist candidates."
Musk has been quick to criticize Trump as well. In May, he said a "less divisive" candidate than Trump would be better for the 2024 presidential run. In 2016, Musk was outraged over the Trump administration's decision to exit the climate-focused Paris Agreement, though in 2018 the SpaceX CEO said he liked Trump's idea for a Space Force military branch in outer space.