KHARKIV, Ukraine—Ukraine is ramping up its defense industry at a Soviet-era tank factory here near Europe’s deadly front line with Russia, as officials wonder what the inauguration of President-elect Donald Trump will mean for their country.

Ukrainian officials say support from the U.S. and other allies is critical to bring its military into the 21st century as Ukrainian troops fight Moscow-backed separatists in the east. But officials also harbor little hope that Mr. Trump will deliver the high-tech weaponry Kiev couldn’t...