diff --git a/icu4c/source/i18n/measunit_extra.cpp b/icu4c/source/i18n/measunit_extra.cpp
index f1d01af4ecc8..28df47a684cd 100644
--- a/icu4c/source/i18n/measunit_extra.cpp
+++ b/icu4c/source/i18n/measunit_extra.cpp
@@ -1488,6 +1488,11 @@ MeasureUnit MeasureUnit::withDimensionality(int32_t dimensionality, UErrorCode&
 
 MeasureUnit MeasureUnit::reciprocal(UErrorCode& status) const {
     MeasureUnitImpl impl = MeasureUnitImpl::forMeasureUnitMaybeCopy(*this, status);
+    // The reciprocal of a unit that has a constant denominator is not allowed.
+    if (impl.constantDenominator != 0) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return {};
+    }
     impl.takeReciprocal(status);
     return std::move(impl).build(status);
 }