diff --git a/flang/lib/Lower/ConvertExpr.cpp b/flang/lib/Lower/ConvertExpr.cpp
--- a/flang/lib/Lower/ConvertExpr.cpp
+++ b/flang/lib/Lower/ConvertExpr.cpp
@@ -1092,7 +1092,9 @@
 
   template <int KIND>
   ExtValue genval(const Fortran::evaluate::SetLength<KIND> &x) {
-    TODO(getLoc(), "genval SetLength<KIND>");
+    mlir::Value newLenValue = genunbox(x.right());
+    fir::ExtendedValue lhs = gen(x.left());
+    return replaceScalarCharacterLength(lhs, newLenValue);
   }
 
   template <int KIND>
diff --git a/flang/test/Lower/set-length.f90 b/flang/test/Lower/set-length.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Lower/set-length.f90
@@ -0,0 +1,28 @@
+! Test evaluate::SetLength lowering (used to set a different length on a
+! character storage around calls where the dummy and actual length differ).
+! RUN: bbc -emit-fir -o - %s | FileCheck %s
+
+
+subroutine takes_length_4(c)
+  character c(3)*4
+  !do i = 1,3
+  print *, c(i)
+  !enddo
+end
+  
+! CHECK-LABEL: func @_QPfoo(
+subroutine foo(c)
+  character c(4)*3
+  ! evaluate::Expr is: CALL s(%SET_LENGTH(c(1_8),4_8)) after semantics.
+  call takes_length_4(c(1))
+! CHECK:         %[[VAL_2:.*]] = arith.constant 4 : i64
+! CHECK:         %[[VAL_6:.*]] = fir.coordinate_of %{{.*}}, %{{.*}} : (!fir.ref<!fir.array<4x!fir.char<1,3>>>, i64) -> !fir.ref<!fir.char<1,3>>
+! CHECK:         %[[VAL_7:.*]] = fir.convert %[[VAL_6]] : (!fir.ref<!fir.char<1,3>>) -> !fir.ref<!fir.char<1,?>>
+! CHECK:         %[[VAL_8:.*]] = fir.convert %[[VAL_2]] : (i64) -> index
+! CHECK:         %[[VAL_9:.*]] = fir.emboxchar %[[VAL_7]], %[[VAL_8]] : (!fir.ref<!fir.char<1,?>>, index) -> !fir.boxchar<1>                                                                   
+! CHECK:         fir.call @_QPtakes_length_4(%[[VAL_9]]) : (!fir.boxchar<1>) -> ()
+end subroutine
+
+  character(3) :: c(4) = ["abc", "def", "ghi", "klm"] 
+  call foo(c)
+end