Partnerships in YouTube and social media marketing describe formal or informal arrangements between creators, brands, agencies, or other channels who work together to co-create content, cross-promote, or share resources. These arrangements can take many shapes, including sponsored videos, product placements, co-hosted streams, long-term ambassador deals, and channel-to-channel shoutouts. Strong partnerships help creators tap into new audiences, add credibility through association, and unlock revenue streams that would be difficult to build alone.