The Trump administration’s planned overhaul of U.S. corporate tax law came under attack Monday from finance ministers of Europe’s five largest economies, voicing the growing anxiety among foreign executives and officials that the proposals would give American firms unfair tax advantages.

In a letter sent to Treasury Secretary Steven Mnuchin, the finance ministers said the U.S. overhaul contains protectionist measures that could violate double-taxation treaties and breach world trade rules. They zeroed in on several technical...