Abstract: Embodiments are disclosed that provide dynamic creative optimization for video advertisements. In certain embodiments, a content creation system receives a request for a video advertisement from a remote computing system. The request represents attributes of a specific recipient. To generate the video advertisement, the content creation system accesses a collection of assets, such as templates and video elements, from which video content can be generated. The content creation system selects a subset of assets from the collection and combines some or all of the selected subset of assets into a composite content file. The content creation system generates (or causes another system to generate) the requested electronic video advertisement or other video content from the composite content file. The content creation system provides the generated video advertisement or other video content in response to the request that was received from the remote computing system.