diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 7658cb5f6737e..460f0fbf077e5 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,27 @@
+*   Fix orders of produced left joins when using `eager_load`.
+
+    A `eager_load` followed by a `left_joins` was always resulting in the `LEFT JOIN`
+    produced by `left_joins` to have precedence over the `LEFT JOIN` produced by
+    the `eager_load` call.
+
+    This was resulting in an invalid SQL query in some cases
+
+    ```ruby
+    Post.select(:id).eager_load(:author).merge(Author.left_joins(:address))
+    ```
+
+    ### Before (Invalid query)
+    ```sql
+    SELECT DISTINCT "posts"."id" FROM "posts" LEFT OUTER JOIN "addresses" ON "addresses"."id" = "authors"."address_id" LEFT OUTER JOIN "authors" ON "authors"."post_id" = "posts"."id"
+    ```
+
+    ### After
+    ```sql
+    SELECT DISTINCT "posts"."id" FROM "posts" LEFT OUTER JOIN "authors" ON "authors"."post_id" = "posts"."id" LEFT OUTER JOIN "addresses" ON "addresses"."id" = "authors"."address_id"
+    ```
+
+    *Edouard Chin*
+
 *   Enable automatically retrying idempotent `#exists?` queries on connection
     errors.
 
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 383505e7c0cd5..4e5d7f44ee43e 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -458,7 +458,7 @@ def apply_join_dependency(eager_loading: group_values.empty?)
         join_dependency = construct_join_dependency(
           eager_load_values | includes_values, Arel::Nodes::OuterJoin
         )
-        relation = except(:includes, :eager_load, :preload).joins!(join_dependency)
+        relation = except(:includes, :eager_load, :preload).left_outer_joins!(join_dependency)
 
         if eager_loading && has_limit_or_offset? && !(
             using_limitable_reflections?(join_dependency.reflections) &&
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 1ca1ef9f3b1b7..488db79fa390f 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -294,6 +294,7 @@ def eager_load(*args)
 
     def eager_load!(*args) # :nodoc:
       self.eager_load_values |= args
+      self.left_outer_joins_values |= args
       self
     end
 
@@ -819,6 +820,7 @@ def unscope!(*args) # :nodoc:
             raise ArgumentError, "Called unscope() with invalid unscoping argument ':#{scope}'. Valid arguments are :#{VALID_UNSCOPING_VALUES.to_a.join(", :")}."
           end
           assert_modifiable!
+          self.left_outer_joins_values -= eager_load_values if scope == :eager_load
           @values.delete(scope)
         when Hash
           scope.each do |key, target_value|
diff --git a/activerecord/test/cases/relation/merging_test.rb b/activerecord/test/cases/relation/merging_test.rb
index 302ee1a87f3e8..2a3bbab053024 100644
--- a/activerecord/test/cases/relation/merging_test.rb
+++ b/activerecord/test/cases/relation/merging_test.rb
@@ -208,6 +208,12 @@ def test_relation_merging_with_eager_load
     end
   end
 
+  def test_relation_merging_with_eager_load_and_left_joins
+    result = Post.eager_load(:author).merge(Author.where.missing(:author_address_extra)).count
+
+    assert_equal(6, result)
+  end
+
   def test_relation_merging_with_locks
     devs = Developer.lock.where("salary >= 80000").order("id DESC").merge(Developer.limit(2))
     assert_predicate devs, :locked?
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
index c849743ae4e94..2cb9c74d39f34 100644
--- a/activerecord/test/cases/scoping/default_scoping_test.rb
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -418,6 +418,16 @@ def test_unscope_eager_load
     assert_equal false, received.first.projects.loaded?
   end
 
+  def test_unscope_eager_load_keeps_left_joins
+    Computer.destroy_all
+
+    expected = Developer.all.collect(&:name)
+    received = Developer.eager_load(:projects).left_joins(:computers).unscope(:eager_load).group("developers.id")
+      .having("COUNT(computers.id) = 0")
+
+    assert_equal expected, received.collect(&:name)
+  end
+
   def test_unscope_preloads
     expected = Developer.all.collect(&:name)
     received = Developer.preload(:projects).select(:id).unscope(:preload, :select)