diff --git a/libqpdf/QPDF_Array.cc b/libqpdf/QPDF_Array.cc
index 4e2813f..ddbeba5 100644
--- a/libqpdf/QPDF_Array.cc
+++ b/libqpdf/QPDF_Array.cc
@@ -174,8 +174,10 @@ Array::null() const
 size_t
 Array::size() const
 {
-    auto a = array();
-    return a->sp ? a->sp->size : a->elements.size();
+    if (auto a = as<QPDF_Array>()) {
+        return a->sp ? a->sp->size : a->elements.size();
+    }
+    return 0;
 }
 
 std::pair<bool, QPDFObjectHandle>
diff --git a/libqpdf/qpdf/QPDFObjectHandle_private.hh b/libqpdf/qpdf/QPDFObjectHandle_private.hh
index 74872b4..447754b 100644
--- a/libqpdf/qpdf/QPDFObjectHandle_private.hh
+++ b/libqpdf/qpdf/QPDFObjectHandle_private.hh
@@ -86,6 +86,7 @@ namespace qpdf
 
         const_reverse_iterator crend();
 
+        // Return the number of elements in the array. Return 0 if the object is not an array.
         size_t size() const;
         std::pair<bool, QPDFObjectHandle> at(int n) const;
         bool setAt(int at, QPDFObjectHandle const& oh);