Embodiments relate to cross-pipe serialization for a multi-pipeline computer processor. An aspect includes receiving, by a processor, the processor comprising a first pipeline, the first pipeline comprising a serialization pipeline, and a second pipeline, the second pipeline comprising a non-serialization pipeline, a request comprising a first subrequest for the first pipeline and a second subrequest for the second pipeline. Another aspect includes completing the first subrequest by the first pipeline. Another aspect includes, based on completing the first subrequest by the first pipeline, sending cross-pipe unlock signal from the first pipeline to the second pipeline. Yet another aspect includes, based on receiving the cross-pipe unlock signal by the second pipeline, completing the second subrequest by the second pipeline.