diff --git a/app/services/exports/export_donations_csv_service.rb b/app/services/exports/export_donations_csv_service.rb
index 9ca5bcb73f..8b5629f538 100644
--- a/app/services/exports/export_donations_csv_service.rb
+++ b/app/services/exports/export_donations_csv_service.rb
@@ -15,6 +15,13 @@ def initialize(donation_ids:, organization:)
       ).order(created_at: :asc)
 
       @organization = organization
+      item_header_names = @organization.items.select("DISTINCT ON (LOWER(name)) items.name").order("LOWER(name) ASC").map(&:name)
+
+      @item_headers = if @organization.include_in_kind_values_in_exported_files
+        item_header_names.flat_map { |header| [header, "#{header} In-Kind Value"] }
+      else
+        item_header_names
+      end
     end
 
     def generate_csv
@@ -42,7 +49,7 @@ def generate_csv_data
 
     def headers
       # Build the headers in the correct order
-      base_headers + item_headers
+      base_headers + @item_headers
     end
 
     # Returns a Hash of keys to indexes so that obtaining the index
@@ -95,24 +102,6 @@ def base_headers
       base_table.keys
     end
 
-    def item_headers
-      return @item_headers if @item_headers
-
-      item_names = Set.new
-
-      donations.each do |donation|
-        donation.line_items.each do |line_item|
-          item_names.add(line_item.item.name)
-        end
-      end
-
-      @item_headers = item_names.sort
-
-      @item_headers = @item_headers.flat_map { |header| [header, "#{header} In-Kind Value"] } if @organization.include_in_kind_values_in_exported_files
-
-      @item_headers
-    end
-
     def build_row_data(donation)
       row = base_table.values.map { |closure| closure.call(donation) }
       row += make_item_quantity_and_value_slots
@@ -128,7 +117,7 @@ def build_row_data(donation)
     end
 
     def make_item_quantity_and_value_slots
-      slots = Array.new(item_headers.size, 0)
+      slots = Array.new(@item_headers.size, 0)
       slots = slots.map.with_index { |value, index| index.odd? ? Money.new(0) : value } if @organization.include_in_kind_values_in_exported_files
       slots
     end
diff --git a/spec/services/exports/export_donations_csv_service_spec.rb b/spec/services/exports/export_donations_csv_service_spec.rb
index 89ec120140..fc21b6ff14 100644
--- a/spec/services/exports/export_donations_csv_service_spec.rb
+++ b/spec/services/exports/export_donations_csv_service_spec.rb
@@ -74,9 +74,11 @@ def source_name(donation)
     end
 
     context 'while "Include in-kind value in donation and distribution exports?" is set to yes' do
-      it 'should match the expected content with in-kind value of each item for the csv' do
+      before do
         allow(organization).to receive(:include_in_kind_values_in_exported_files).and_return(true)
+      end
 
+      it 'should match the expected content with in-kind value of each item for the csv' do
         csv = <<~CSV
           Source,Date,Details,Storage Location,Quantity of Items,Variety of Items,In-Kind Total,Comments,A Item,A Item In-Kind Value,B Item,B Item In-Kind Value,C Item,C Item In-Kind Value,Dupe Item,Dupe Item In-Kind Value,E Item,E Item In-Kind Value
           Product Drive,2025-01-01,#{source_name(donations[0])},Test Storage Location,15,2,94.0,It's a fine day for diapers.,7,70.00,0,0.00,0,0.00,8,24.00,0,0.00
@@ -86,6 +88,212 @@ def source_name(donation)
         CSV
         expect(subject).to eq(csv)
       end
+
+      it 'should include inactive items in the export' do
+        inactive_item = create(:item, :inactive, name: "Inactive Item", organization: organization)
+        csv_data = described_class.new(donation_ids: donation_ids, organization: organization).generate_csv_data
+
+        # Verify the inactive item appears in headers
+        expect(csv_data[0][18]).to eq(inactive_item.name)
+        expect(csv_data[0][19]).to eq("#{inactive_item.name} In-Kind Value")
+
+        # Verify all rows have 0 quantity for the inactive item
+        csv_data[1..].each do |row|
+          expect(row[18]).to eq(0)
+          expect(row[19]).to eq(0)
+        end
+      end
+
+      it 'should include items that are not in any donation' do
+        unused_item = create(:item, name: "Unused Item", organization: organization)
+        csv_data = described_class.new(donation_ids: donation_ids, organization: organization).generate_csv_data
+
+        # Verify the unused item appears in headers
+        expect(csv_data[0][18]).to include(unused_item.name)
+        expect(csv_data[0][19]).to include("#{unused_item.name} In-Kind Value")
+
+        # Verify all rows have 0 quantity for the unused item
+        csv_data[1..].each do |row|
+          expect(row[18]).to eq(0)
+          expect(row[19]).to eq(0)
+        end
+      end
+    end
+  end
+
+  describe '#generate_csv_data' do
+    let(:organization) { create(:organization) }
+    let(:generated_csv_data) { described_class.new(donation_ids: donation_ids, organization: organization).generate_csv_data }
+    let(:donation_ids) { donations.map(&:id) }
+    let(:duplicate_item) { create(:item, organization: organization) }
+    let(:items_lists) do
+      [
+        [
+          [duplicate_item, 5],
+          [create(:item, organization: organization), 7],
+          [duplicate_item, 3]
+        ],
+        *(Array.new(3) do |i|
+          [[create(
+            :item, name: "item_#{i}", organization: organization
+          ), i + 1]]
+        end)
+      ]
+    end
+
+    let(:base_headers) do
+      described_class.new(donation_ids: [], organization: organization).send(:base_headers)
+    end
+
+    let(:item_names) { items_lists.flatten(1).map(&:first).map(&:name).sort.uniq }
+
+    let(:donations) do
+      start_time = Time.current
+
+      items_lists.each_with_index.map do |items, i|
+        donation = create(
+          :donation,
+          organization: organization,
+          donation_site: create(
+            :donation_site, name: "Space Needle #{i}", organization: organization
+          ),
+          issued_at: start_time + i.days,
+          comment: "This is the #{i}-th donation in the test."
+        )
+
+        items.each do |(item, quantity)|
+          donation.line_items << create(
+            :line_item, quantity: quantity, item: item
+          )
+        end
+
+        donation
+      end
+    end
+
+    let(:expected_headers) do
+      [
+        "Source",
+        "Date",
+        "Details",
+        "Storage Location",
+        "Quantity of Items",
+        "Variety of Items",
+        "In-Kind Total",
+        "Comments"
+      ] + expected_item_headers
+    end
+
+    let(:total_item_quantities) do
+      template = item_names.index_with(0)
+
+      items_lists.map do |items_list|
+        row = template.dup
+        items_list.each do |(item, quantity)|
+          row[item.name] += quantity
+        end
+        row.values
+      end
+    end
+
+    let(:expected_item_headers) do
+      expect(item_names).not_to be_empty
+
+      item_names
+    end
+
+    it 'should match the expected content for the csv' do
+      expect(generated_csv_data[0]).to eq(expected_headers)
+
+      donations.zip(total_item_quantities).each_with_index do |(donation, total_item_quantity), idx|
+        row = [
+          donation.source,
+          donation.issued_at.strftime("%F"),
+          donation.details,
+          donation.storage_view,
+          donation.line_items.total,
+          total_item_quantity.count(&:positive?),
+          donation.in_kind_value_money,
+          donation.comment
+        ]
+
+        row += total_item_quantity
+
+        expect(generated_csv_data[idx + 1]).to eq(row)
+      end
+    end
+
+    context 'when an organization\'s item exists but isn\'t in any donation' do
+      let!(:unused_item) { create(:item, name: "Unused Item", organization: organization) }
+      let!(:generated_csv_data) do
+        described_class.new(donation_ids: donations.map(&:id), organization: organization).generate_csv_data
+      end
+
+      it 'should include the unused item as a column with 0 quantities' do
+        expect(generated_csv_data[0][13]).to eq(unused_item.name)
+
+        donations.each_with_index do |_, idx|
+          row = generated_csv_data[idx + 1]
+          expect(row[13]).to eq(0)
+        end
+      end
+    end
+
+    context 'when an organization\'s item is inactive' do
+      let!(:inactive_item) { create(:item, name: "Inactive Item", organization: organization, active: false) }
+      let!(:generated_csv_data) do
+        described_class.new(donation_ids: donations.map(&:id), organization: organization).generate_csv_data
+      end
+
+      it 'should include the inactive item as a column with 0 quantities' do
+        expect(generated_csv_data[0][10]).to include(inactive_item.name)
+
+        donations.each_with_index do |_, idx|
+          row = generated_csv_data[idx + 1]
+          expect(row[10]).to eq(0)
+        end
+      end
+    end
+
+    context 'when generating CSV output' do
+      let(:generated_csv) { described_class.new(donation_ids: donation_ids, organization: organization).generate_csv }
+
+      it 'returns a valid CSV string' do
+        expect(generated_csv).to be_a(String)
+        expect { CSV.parse(generated_csv) }.not_to raise_error
+      end
+
+      it 'includes headers as first row' do
+        csv_rows = CSV.parse(generated_csv)
+        expect(csv_rows.first).to eq(expected_headers)
+      end
+
+      it 'includes data for all donations' do
+        csv_rows = CSV.parse(generated_csv)
+        expect(csv_rows.count).to eq(donations.count + 1) # +1 for headers
+      end
+    end
+
+    context 'when items have different cases' do
+      let(:item_names) { ["Zebra", "apple", "Banana"] }
+      let(:expected_order) { ["apple", "Banana", "Zebra"] }
+      let(:donation) { create(:donation, organization: organization) }
+      let(:case_sensitive_csv_data) do
+        # Create items in random order to ensure sort is working
+        item_names.shuffle.each do |name|
+          create(:item, name: name, organization: organization)
+        end
+
+        described_class.new(donation_ids: [donation.id], organization: organization).generate_csv_data
+      end
+
+      it 'should sort item columns case-insensitively, ASC' do
+        # Get just the item columns by removing the known base headers
+        item_columns = case_sensitive_csv_data[0] - base_headers
+
+        # Check that the remaining columns match our expected case-insensitive sort
+        expect(item_columns).to eq(expected_order)
+      end
     end
   end
 end