No — that's a well-known misrepresentation of what he actually said.

In his 2010 TED Talk "Innovating to zero!", Gates discussed how to reduce CO₂ emissions. As part of an equation about emissions, he noted the world population was headed toward 9 billion and said: "if we do a really great job on new vaccines, health care, reproductive health services, we could lower that by perhaps 10 or 15 percent."

His point was about slowing population growth, not reducing the existing population. Gates has consistently argued the opposite of the conspiracy reading: when child mortality falls thanks to vaccines and better healthcare, parents choose to have fewer children, so birth rates drop and population growth levels off. He was not saying vaccines would kill or sterilize people. ( AP News,  FactCheck.org)

The clip has been repeatedly taken out of context — sometimes through misleading edits — to suggest a "depopulation" plan, and fact-checkers including Reuters, Snopes, Full Fact, PolitiFact and AFP have all debunked that interpretation. ( Poynter,  Full Fact,  AFP)

The full talk and transcript are publicly available on TED's website if you want to judge the context yourself.