diff --git a/include/qpdf/QPDFNameTreeObjectHelper.hh b/include/qpdf/QPDFNameTreeObjectHelper.hh
index 12950d0..1db1241 100644
--- a/include/qpdf/QPDFNameTreeObjectHelper.hh
+++ b/include/qpdf/QPDFNameTreeObjectHelper.hh
@@ -50,7 +50,13 @@ class QPDF_DLL_CLASS QPDFNameTreeObjectHelper: public QPDFObjectHelper
         QPDFObjectHandle,
         QPDF&,
         std::function<bool(QPDFObjectHandle const&)> value_validator,
-        bool auto_repair = true);
+        bool auto_repair);
+
+    // Validate the name tree. Returns true if the tree is valid.
+    //
+    // If the tree is not valid and auto_repair is true, attempt to repair the tree.
+    QPDF_DLL
+    bool validate(bool repair = true);
 
     // Create an empty name tree
     QPDF_DLL
diff --git a/include/qpdf/QPDFNumberTreeObjectHelper.hh b/include/qpdf/QPDFNumberTreeObjectHelper.hh
index ec06fd3..5d6c669 100644
--- a/include/qpdf/QPDFNumberTreeObjectHelper.hh
+++ b/include/qpdf/QPDFNumberTreeObjectHelper.hh
@@ -48,7 +48,7 @@ class QPDF_DLL_CLASS QPDFNumberTreeObjectHelper: public QPDFObjectHelper
         QPDFObjectHandle,
         QPDF&,
         std::function<bool(QPDFObjectHandle const&)> value_validator,
-        bool auto_repair = true);
+        bool auto_repair);
 
     QPDF_DLL
     ~QPDFNumberTreeObjectHelper() override;
@@ -59,6 +59,12 @@ class QPDF_DLL_CLASS QPDFNumberTreeObjectHelper: public QPDFObjectHelper
 
     typedef long long int numtree_number;
 
+    // Validate the name tree. Returns true if the tree is valid.
+    //
+    // If the tree is not valid and auto_repair is true, attempt to repair the tree.
+    QPDF_DLL
+    bool validate(bool repair = true);
+
     // Return overall minimum and maximum indices
     QPDF_DLL
     numtree_number getMin();
diff --git a/libqpdf/NNTree.cc b/libqpdf/NNTree.cc
index f22dbc2..d3ff3b6 100644
--- a/libqpdf/NNTree.cc
+++ b/libqpdf/NNTree.cc
@@ -891,3 +891,33 @@ NNTreeImpl::remove(QPDFObjectHandle const& key, QPDFObjectHandle* value)
     iter.remove();
     return true;
 }
+
+bool
+NNTreeImpl::validate(bool a_repair)
+{
+    bool first = true;
+    QPDFObjectHandle last_key;
+    try {
+        for (auto const& [key, value]: *this) {
+            if (!details.keyValid(key)) {
+                error(oh, "invalid key in validate");
+            }
+            if (!value_valid(value)) {
+                error(oh, "invalid value in validate");
+            }
+            if (first) {
+                first = false;
+            } else if (last_key && details.compareKeys(last_key, key) != -1) {
+                error(oh, "keys are not sorted in validate");
+            }
+            last_key = key;
+        }
+    } catch (QPDFExc& e) {
+        if (a_repair) {
+            warn(oh, std::string("attempting to repair after error: ") + e.what());
+            repair();
+        }
+        return false;
+    }
+    return true;
+}
diff --git a/libqpdf/QPDFNameTreeObjectHelper.cc b/libqpdf/QPDFNameTreeObjectHelper.cc
index b6344ec..d3bccf3 100644
--- a/libqpdf/QPDFNameTreeObjectHelper.cc
+++ b/libqpdf/QPDFNameTreeObjectHelper.cc
@@ -215,3 +215,9 @@ QPDFNameTreeObjectHelper::getAsMap() const
     result.insert(begin(), end());
     return result;
 }
+
+bool
+QPDFNameTreeObjectHelper::validate(bool repair)
+{
+    return m->impl->validate(repair);
+}
diff --git a/libqpdf/QPDFNumberTreeObjectHelper.cc b/libqpdf/QPDFNumberTreeObjectHelper.cc
index 297c67d..eae8251 100644
--- a/libqpdf/QPDFNumberTreeObjectHelper.cc
+++ b/libqpdf/QPDFNumberTreeObjectHelper.cc
@@ -251,3 +251,9 @@ QPDFNumberTreeObjectHelper::getAsMap() const
     result.insert(begin(), end());
     return result;
 }
+
+bool
+QPDFNumberTreeObjectHelper::validate(bool repair)
+{
+    return m->impl->validate(repair);
+}
diff --git a/libqpdf/qpdf/NNTree.hh b/libqpdf/qpdf/NNTree.hh
index ac266db..fcaf401 100644
--- a/libqpdf/qpdf/NNTree.hh
+++ b/libqpdf/qpdf/NNTree.hh
@@ -109,6 +109,8 @@ class NNTreeImpl
     iterator insert(QPDFObjectHandle const& key, QPDFObjectHandle const& value);
     bool remove(QPDFObjectHandle const& key, QPDFObjectHandle* value = nullptr);
 
+    bool validate(bool repair = true);
+
     // Change the split threshold for easier testing. There's no real reason to expose this to
     // downstream tree helpers, but it has to be public so we can call it from the test suite.
     void setSplitThreshold(int split_threshold);