diff --git a/gcc/c-family/c-ada-spec.cc b/gcc/c-family/c-ada-spec.cc
--- a/gcc/c-family/c-ada-spec.cc
+++ b/gcc/c-family/c-ada-spec.cc
@@ -3440,16 +3440,26 @@ dump_ada_structure (pretty_printer *buffer, tree node, tree type, bool nested,
       pp_string (buffer, "Unchecked_Union => True");
     }
 
-  if (bitfield_used || packed_layout)
+  const bool needs_pack = bitfield_used || packed_layout;
+
+  if (needs_pack)
     {
-      char buf[32];
       pp_comma (buffer);
       newline_and_indent (buffer, spc + 5);
       pp_string (buffer, "Pack => True");
+    }
+
+  if (needs_pack || TYPE_USER_ALIGN (node))
+    {
+      char buf[32];
       pp_comma (buffer);
       newline_and_indent (buffer, spc + 5);
       sprintf (buf, "Alignment => %d", TYPE_ALIGN (node) / BITS_PER_UNIT);
       pp_string (buffer, buf);
+    }
+
+  if (needs_pack)
+    {
       bitfield_used = false;
       packed_layout = false;
     }
diff --git a/gcc/testsuite/g++.dg/ada-spec/explicit-alignment.C b/gcc/testsuite/g++.dg/ada-spec/explicit-alignment.C
new file mode 100644
index 000000000..1450e6b84
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ada-spec/explicit-alignment.C
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-ada-spec-slim" } */
+/* { dg-final { scan-file explicit_alignment_c.ads "Alignment => 32" } } */
+
+struct alignas(32) Aligned
+{
+  int value;
+};
+
+extern "C" unsigned long cpp_size () { return sizeof (Aligned); }
+extern "C" unsigned long cpp_alignment () { return alignof (Aligned); }
+
+/* { dg-final { cleanup-ada-spec } } */