diff --git a/flang/lib/Semantics/check-call.cpp b/flang/lib/Semantics/check-call.cpp
--- a/flang/lib/Semantics/check-call.cpp
+++ b/flang/lib/Semantics/check-call.cpp
@@ -535,7 +535,8 @@
             // 15.5.2.9(1): if dummy is not pure, actual need not be.
             argInterface.attrs.reset(characteristics::Procedure::Attr::Pure);
           }
-          if (interface.HasExplicitInterface()) {
+          if (interface.HasExplicitInterface() &&
+              argInterface.HasExplicitInterface()) {
             if (interface != argInterface) {
               messages.Say(
                   "Actual argument procedure has interface incompatible with %s"_err_en_US,
diff --git a/flang/test/Semantics/call09.f90 b/flang/test/Semantics/call09.f90
--- a/flang/test/Semantics/call09.f90
+++ b/flang/test/Semantics/call09.f90
@@ -19,6 +19,9 @@
   subroutine s02(p)
     procedure(realfunc), pointer :: p
   end subroutine
+  subroutine s03(p)
+    procedure(realfunc) :: p
+  end subroutine
 
   subroutine selemental1(p)
     procedure(cos) :: p ! ok
@@ -47,6 +50,9 @@
     procedure(realfunc), pointer :: p
     procedure(intfunc), pointer :: ip
     integer, pointer :: intPtr
+    external :: extfunc
+    external :: extfuncPtr
+    pointer :: extfuncPtr
     p => realfunc
     ip => intfunc
     call s01(realfunc) ! ok
@@ -65,6 +71,7 @@
     call s01(null(intPtr))
     !ERROR: Actual argument associated with procedure dummy argument 'p=' is not a procedure
     call s01(B"0101")
+    call s01(extfunc) ! ok
     !ERROR: Actual argument associated with procedure pointer dummy argument 'p=' must be a POINTER unless INTENT(IN)
     call s02(realfunc)
     call s02(p) ! ok
@@ -78,6 +85,9 @@
     call s02(null(p))
     !ERROR: Actual argument associated with procedure pointer dummy argument 'p=' must be a POINTER unless INTENT(IN)
     call s02(sin)
+    !ERROR: Actual argument associated with procedure pointer dummy argument 'p=' must be a POINTER unless INTENT(IN)
+    call s02(extfunc) ! ok
+    call s03(extfuncPtr) ! ok
   end subroutine
 
   subroutine callsub(s)