diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index af2175f2104e2328c9e8c50209fac4c43a4fe64f..0c79c0edde52b56c7da8720caa03b7411090e7ab 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -260,7 +260,7 @@ def self.available_state_names
 
   state_machine :merge_status, initial: :unchecked do
     event :mark_as_preparing do
-      transition unchecked: :preparing
+      transition [:unchecked, :can_be_merged] => :preparing
     end
 
     event :mark_as_unchecked do
diff --git a/app/models/merge_requests/merge_data.rb b/app/models/merge_requests/merge_data.rb
index 9d5c7a0823d17413d68bb197cb3e9b755ce94c2a..4e5db754f85afb480054de61ab3dc210a567a1d6 100644
--- a/app/models/merge_requests/merge_data.rb
+++ b/app/models/merge_requests/merge_data.rb
@@ -40,7 +40,7 @@ class MergeData < ApplicationRecord
 
     state_machine :merge_status, initial: :unchecked do
       event :mark_as_preparing do
-        transition unchecked: :preparing
+        transition [:unchecked, :can_be_merged] => :preparing
       end
 
       event :mark_as_unchecked do
diff --git a/app/services/suggestions/apply_service.rb b/app/services/suggestions/apply_service.rb
index 43c178295bb0129e2a264c19f29d42944f6240e3..79737854380a78d0a03d86c72f951c6d2235532f 100644
--- a/app/services/suggestions/apply_service.rb
+++ b/app/services/suggestions/apply_service.rb
@@ -23,6 +23,7 @@ def execute
     def result
       multi_service.execute.tap do |result|
         update_suggestions(result)
+        update_associated_merge_request(result)
       end
     end
 
@@ -36,6 +37,12 @@ def update_suggestions(result)
         .track_apply_suggestion_action(user: current_user, suggestions: suggestion_set.suggestions)
     end
 
+    def update_associated_merge_request(result)
+      return unless result[:status] == :success
+
+      suggestion_set.merge_request.mark_as_preparing
+    end
+
     def author
       authors = suggestion_set.authors
 
diff --git a/lib/gitlab/suggestions/suggestion_set.rb b/lib/gitlab/suggestions/suggestion_set.rb
index 21a5acf8afe49faa70becad254148a348e9d16ea..2e91fe4c6808e5fdc56730286f29621c7faa0c89 100644
--- a/lib/gitlab/suggestions/suggestion_set.rb
+++ b/lib/gitlab/suggestions/suggestion_set.rb
@@ -21,6 +21,10 @@ def branch
         first_suggestion.branch
       end
 
+      def merge_request
+        first_suggestion.noteable
+      end
+
       def valid?
         error_message.nil?
       end
diff --git a/spec/lib/gitlab/suggestions/suggestion_set_spec.rb b/spec/lib/gitlab/suggestions/suggestion_set_spec.rb
index 4a822717c78863bec71024e9ad3d1d437386b679..a43f09d0bc96996d6203d90f33ccce7b6a04a1d6 100644
--- a/spec/lib/gitlab/suggestions/suggestion_set_spec.rb
+++ b/spec/lib/gitlab/suggestions/suggestion_set_spec.rb
@@ -74,6 +74,12 @@ def create_suggestion(file_path, new_line, to_content)
       end
     end
 
+    describe '#merge_request' do
+      it 'returns the merge_request associated with the suggestions' do
+        expect(suggestion_set.merge_request).to eq(merge_request)
+      end
+    end
+
     describe '#valid?' do
       it 'returns true if no errors are found' do
         expect(suggestion_set.valid?).to be(true)
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 97764ed2bbfe60c4311284588ea0ef4cb57e122c..06ff0ad8a9dae344a1c85f9c66930fe4a70ce2a6 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -5869,14 +5869,15 @@ def transition!
         it_behaves_like 'transition not triggering mergeRequestMergeStatusUpdated GraphQL subscription'
       end
 
-      context 'when the status is checking' do
-        let(:merge_status) { :checking }
+      context 'when the status is can_be_merged' do
+        let(:merge_status) { :can_be_merged }
 
-        include_examples 'for an invalid state transition'
+        include_examples 'for a valid state transition'
+        it_behaves_like 'transition not triggering mergeRequestMergeStatusUpdated GraphQL subscription'
       end
 
-      context 'when the status is can_be_merged' do
-        let(:merge_status) { :can_be_merged }
+      context 'when the status is checking' do
+        let(:merge_status) { :checking }
 
         include_examples 'for an invalid state transition'
       end
diff --git a/spec/models/merge_requests/merge_data_spec.rb b/spec/models/merge_requests/merge_data_spec.rb
index 7f1af1544ff419171b0fd89892f111f25f8a0035..f22e2bb4119392ab4e4a566b9a398db0c26cb40c 100644
--- a/spec/models/merge_requests/merge_data_spec.rb
+++ b/spec/models/merge_requests/merge_data_spec.rb
@@ -75,7 +75,7 @@ def transition!
         context 'when the status is can_be_merged' do
           let(:merge_status) { :can_be_merged }
 
-          include_examples 'for an invalid state transition'
+          include_examples 'for a valid state transition'
         end
 
         context 'when the status is cannot_be_merged_recheck' do
diff --git a/spec/services/suggestions/apply_service_spec.rb b/spec/services/suggestions/apply_service_spec.rb
index 1f950548185b27de2bb5534cec0fefdc04d14839..81dc8c2e2523e8a1f3402beac756969e511f2a57 100644
--- a/spec/services/suggestions/apply_service_spec.rb
+++ b/spec/services/suggestions/apply_service_spec.rb
@@ -76,6 +76,13 @@ def apply(suggestions, custom_message = nil)
       expect(commit.committer_name).to eq(user.name)
     end
 
+    it 'transitions MR state to preparing' do
+      expect do
+        apply(suggestions)
+        merge_request.reload
+      end.to change { merge_request.merge_status }.from('can_be_merged').to('preparing')
+    end
+
     it 'tracks apply suggestion event' do
       expect(Gitlab::UsageDataCounters::MergeRequestActivityUniqueCounter)
         .to receive(:track_apply_suggestion_action)
@@ -636,6 +643,9 @@ def popen(cmd, path=nil)
           message: "You are not allowed to push into this branch",
           status: :error
         )
+
+        expect(merge_request)
+          .not_to receive(:mark_as_preparing)
       end
     end
   end