diff --git a/app/models/exports/concerns/csv.rb b/app/models/exports/concerns/csv.rb
index cc1c7b59e542..859e6e0ccaa6 100644
--- a/app/models/exports/concerns/csv.rb
+++ b/app/models/exports/concerns/csv.rb
@@ -53,7 +53,7 @@ def success(serialized)
         ::Exports::Result
           .new format: :csv,
                title: csv_export_filename,
-               content: serialized,
+               content: "\xEF\xBB\xBF#{serialized}", # Make Excel open CSV happy by append UTF8 BOM
                mime_type: "text/csv"
       end
 
diff --git a/spec/models/projects/exporter/csv_integration_spec.rb b/spec/models/projects/exporter/csv_integration_spec.rb
index e578ab18bc65..11dcb17aa1db 100644
--- a/spec/models/projects/exporter/csv_integration_spec.rb
+++ b/spec/models/projects/exporter/csv_integration_spec.rb
@@ -74,7 +74,7 @@
       it "does not render project custom fields in the header" do
         expect(parsed.size).to eq 2
 
-        expect(header).to eq ["id", "Identifier", "Name", "Description", "Status", "Public"]
+        expect(header).to eq ["\xEF\xBB\xBFid", "Identifier", "Name", "Description", "Status", "Public"]
       end
 
       it "does not render the custom field values in the rows if enabled for a project" do
@@ -93,7 +93,7 @@
         expect(cf_names).not_to include(not_used_string_cf.name)
         expect(cf_names).not_to include(hidden_cf.name)
 
-        expect(header).to eq ["id", "Identifier", "Name", "Description", "Status", "Public", *cf_names]
+        expect(header).to eq ["\xEF\xBB\xBFid", "Identifier", "Name", "Description", "Status", "Public", *cf_names]
       end
 
       it "renders the custom field values in the rows if enabled for a project" do
@@ -126,7 +126,7 @@
         expect(cf_names).to include(not_used_string_cf.name)
         expect(cf_names).to include(hidden_cf.name)
 
-        expect(header).to eq ["id", "Identifier", "Name", "Description", "Status", "Public", *cf_names]
+        expect(header).to eq ["\xEF\xBB\xBFid", "Identifier", "Name", "Description", "Status", "Public", *cf_names]
       end
 
       it "renders the custom field values in the rows if enabled for a project" do
diff --git a/spec/models/work_package/exporter/csv_integration_spec.rb b/spec/models/work_package/exporter/csv_integration_spec.rb
index f2c0ef5e4163..fb76f70c6b2d 100644
--- a/spec/models/work_package/exporter/csv_integration_spec.rb
+++ b/spec/models/work_package/exporter/csv_integration_spec.rb
@@ -124,7 +124,7 @@
       data = CSV.parse instance.export!.content
 
       expect(data.size).to eq(5)
-      expect(data.pluck(0)).to eq ["Type", "Type A", "Type A", "Type A", "Type B"]
+      expect(data.pluck(0)).to eq ["\xEF\xBB\xBFType", "Type A", "Type A", "Type A", "Type B"]
     end
   end
 
@@ -171,7 +171,7 @@
       data = CSV.parse instance.export!.content
 
       expect(data.size).to eq(5)
-      expect(data.pluck(0)).to eq %w[Subject WP4 WP2 WP1 WP3]
+      expect(data.pluck(0)).to eq %w[WP4 WP2 WP1 WP3].unshift("\xEF\xBB\xBFSubject")
     end
   end
 end