diff --git a/.tool-versions b/.tool-versions
index ca745c6d..3f03c7a7 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1 +1 @@
-ruby 3.4.4
+ruby 3.4.7
diff --git a/lib/closure_tree/support.rb b/lib/closure_tree/support.rb
index 9faa9b5a..c13676d0 100644
--- a/lib/closure_tree/support.rb
+++ b/lib/closure_tree/support.rb
@@ -51,8 +51,19 @@ def hierarchy_table_name
       # We need to use the table_name, not something like ct_class.to_s.demodulize + "_hierarchies",
       # because they may have overridden the table name, which is what we want to be consistent with
       # in order for the schema to make sense.
-      tablename = options[:hierarchy_table_name] ||
-                  "#{remove_prefix_and_suffix(table_name, model_class).singularize}_hierarchies"
+      if options[:hierarchy_table_name]
+        tablename = options[:hierarchy_table_name]
+      else
+        base_table = remove_prefix_and_suffix(table_name, model_class)
+
+        # Handle PostgreSQL schema-qualified table names (e.g., "my_schema.table_name")
+        schema, _, table = base_table.rpartition('.')
+        if schema.present?
+          tablename = "#{schema}.#{table.singularize}_hierarchies"
+        else
+          tablename = "#{table.singularize}_hierarchies"
+        end
+      end
 
       [model_class.table_name_prefix, tablename, model_class.table_name_suffix].join
     end
diff --git a/test/closure_tree/schema_type_test.rb b/test/closure_tree/schema_type_test.rb
new file mode 100644
index 00000000..3480581e
--- /dev/null
+++ b/test/closure_tree/schema_type_test.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+describe SchemaType do
+  before do
+    skip 'PostgreSQL only' unless postgresql?
+  end
+
+  def assert_lineage(parent, child)
+    assert_equal parent, child.parent
+    assert_equal [child, parent], child.self_and_ancestors
+
+    # make sure reloading doesn't affect the self_and_ancestors:
+    child.reload
+    assert_equal [child, parent], child.self_and_ancestors
+  end
+
+  it 'properly handles schema-qualified table names' do
+    assert_equal 'test_schema.schema_types', SchemaType.table_name
+    assert_equal 'test_schema.schema_type_hierarchies', SchemaTypeHierarchy.table_name
+  end
+
+  it 'finds self and parents when children << is used' do
+    parent = SchemaType.new(name: 'Electronics')
+    child = SchemaType.new(name: 'Phones')
+    parent.children << child
+    parent.save
+    assert_lineage(parent, child)
+  end
+
+  it 'finds self and parents properly if the constructor is used' do
+    parent = SchemaType.create(name: 'Electronics')
+    child = SchemaType.create(name: 'Phones', parent: parent)
+    assert_lineage(parent, child)
+  end
+
+  it 'creates hierarchy records in the schema-qualified table' do
+    parent = SchemaType.create!(name: 'Electronics')
+    child = SchemaType.create!(name: 'Phones', parent: parent)
+
+    hierarchy = SchemaTypeHierarchy.where(ancestor_id: parent.id, descendant_id: child.id).first
+    refute_nil hierarchy
+    assert_equal 1, hierarchy.generations
+  end
+
+  it 'fixes self_and_ancestors properly on reparenting' do
+    a = SchemaType.create! name: 'Electronics'
+    b = SchemaType.create! name: 'Phones'
+    assert_equal([b], b.self_and_ancestors.to_a)
+    a.children << b
+    assert_equal([b, a], b.self_and_ancestors.to_a)
+  end
+
+  it 'supports tree operations with schema-qualified tables' do
+    root = SchemaType.create!(name: 'Electronics')
+    child1 = SchemaType.create!(name: 'Computers', parent: root)
+    child2 = SchemaType.create!(name: 'Phones', parent: root)
+    grandchild = SchemaType.create!(name: 'Laptops', parent: child1)
+
+    assert_equal 2, root.children.count
+    assert_equal 1, child1.children.count
+    assert_equal 0, child2.children.count
+    assert_equal [grandchild, child1, root], grandchild.self_and_ancestors
+    assert_equal [root, child1, child2, grandchild], root.self_and_descendants.order(:name)
+  end
+end
diff --git a/test/dummy/app/models/schema_type.rb b/test/dummy/app/models/schema_type.rb
new file mode 100644
index 00000000..76fc99c0
--- /dev/null
+++ b/test/dummy/app/models/schema_type.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class SchemaType < ApplicationRecord
+  self.table_name = 'test_schema.schema_types'
+  has_closure_tree order: :name
+
+  def to_s
+    name
+  end
+end
diff --git a/test/dummy/db/schema.rb b/test/dummy/db/schema.rb
index 6994077c..8884f4f2 100644
--- a/test/dummy/db/schema.rb
+++ b/test/dummy/db/schema.rb
@@ -112,6 +112,20 @@
     t.integer 'generations', null: false
   end
 
+  # PostgreSQL schema-qualified tables
+  execute "CREATE SCHEMA IF NOT EXISTS test_schema"
+
+  create_table 'test_schema.schema_types', force: true do |t|
+    t.string 'name'
+    t.references 'parent'
+  end
+
+  create_table 'test_schema.schema_type_hierarchies', id: false, force: true do |t|
+    t.references 'ancestor', null: false
+    t.references 'descendant', null: false
+    t.integer 'generations', null: false
+  end
+
   create_table 'metal' do |t|
     t.references 'parent'
     t.string 'metal_type'