diff --git a/app/lib/reports/systm_one_exporter.rb b/app/lib/reports/systm_one_exporter.rb
new file mode 100644
index 0000000000..11469de6cf
--- /dev/null
+++ b/app/lib/reports/systm_one_exporter.rb
@@ -0,0 +1,187 @@
+# frozen_string_literal: true
+
+class Reports::SystmOneExporter
+  GENDER_CODE_MAPPINGS = {
+    male: "M",
+    female: "F",
+    not_specified: "U",
+    not_known: "U"
+  }.with_indifferent_access.freeze
+
+  VACCINE_DOSE_MAPPINGS = {
+    "Gardasil 9" => {
+      "1" => "Y19a4",
+      "2" => "Y19a5",
+      "3" => "Y19a6"
+    }
+  }.freeze
+
+  DELIVERY_SITE_MAPPINGS = {
+    left_arm_upper_position: "Left deltoid",
+    left_arm_lower_position: "Left anterior forearm",
+    left_thigh: "Left lateral thigh",
+    right_arm_upper_position: "Right deltoid",
+    right_arm_lower_position: "Right anterior forearm",
+    right_thigh: "Right lateral thigh"
+  }.with_indifferent_access.freeze
+
+  def initialize(organisation:, programme:, start_date:, end_date:)
+    @organisation = organisation
+    @programme = programme
+    @start_date = start_date
+    @end_date = end_date
+  end
+
+  def call
+    CSV.generate(headers:, write_headers: true) do |csv|
+      vaccination_records.each do |vaccination_record|
+        csv << row(vaccination_record:)
+      end
+    end
+  end
+
+  def self.call(*args, **kwargs)
+    new(*args, **kwargs).call
+  end
+
+  private_class_method :new
+
+  private
+
+  attr_reader :organisation, :programme, :start_date, :end_date
+
+  def headers
+    [
+      "Practice code",
+      "NHS number",
+      "Surname",
+      "Middle name",
+      "Forename",
+      "Gender",
+      "Date of Birth",
+      "House name",
+      "House number and road",
+      "Town",
+      "Postcode",
+      "Vaccination",
+      "Part",
+      "Admin date",
+      "Batch number",
+      "Expiry date",
+      "Dose",
+      "Reason",
+      "Site",
+      "Method",
+      "Notes"
+    ]
+  end
+
+  def vaccination_records
+    scope =
+      programme
+        .vaccination_records
+        .joins(:organisation)
+        .where(organisations: { id: organisation.id })
+        .merge(VaccinationRecord.administered)
+        .includes(:batch, :location, :programme, :vaccine, :patient)
+
+    if start_date.present?
+      scope =
+        scope.where(
+          "vaccination_records.created_at >= ?",
+          start_date.beginning_of_day
+        ).or(
+          scope.where(
+            "vaccination_records.updated_at >= ?",
+            start_date.beginning_of_day
+          )
+        )
+    end
+
+    if end_date.present?
+      scope =
+        scope.where(
+          "vaccination_records.created_at <= ?",
+          end_date.end_of_day
+        ).or(
+          scope.where(
+            "vaccination_records.updated_at <= ?",
+            end_date.end_of_day
+          )
+        )
+    end
+
+    scope
+  end
+
+  def row(vaccination_record:)
+    patient = vaccination_record.patient
+
+    [
+      practice_code(vaccination_record), # Practice code
+      patient.nhs_number, # NHS number
+      patient.family_name, # Surname
+      "", # Middle name (not stored)
+      patient.given_name, # Forename
+      gender_code(patient.gender_code), # Gender
+      patient.date_of_birth.to_fs(:uk_short),
+      patient.address_line_2, # House name
+      patient.address_line_1, # House number and road
+      patient.address_town, # Town
+      patient.address_postcode, # Postcode
+      vaccination(vaccination_record), # Vaccination
+      "", # Part
+      vaccination_record.performed_at.to_date.to_fs(:uk_short), # Admin date
+      vaccination_record.batch&.name, # Batch number
+      vaccination_record.batch&.expiry&.to_fs(:uk_short), # Expiry date
+      vaccination_record.dose_volume_ml, # Dose
+      reason(vaccination_record), # Reason (not specified)
+      site(vaccination_record), # Site
+      vaccination_record.delivery_method, # Method
+      vaccination_record.notes # Notes
+    ]
+  end
+
+  # TODO: Needs support for community and generic clinics.
+  def practice_code(vaccination_record)
+    location = vaccination_record.session.location
+
+    location.school? ? location.urn : location.ods_code
+  end
+
+  def gender_code(code)
+    GENDER_CODE_MAPPINGS[code]
+  end
+
+  # TODO: These mappings are valid for Hertforshire, but may not be correct for
+  #       other SAIS teams. We'll need to check these are correct with new SAIS
+  #       teams.
+  def vaccination(vaccination_record)
+    return if vaccination_record.not_administered?
+
+    VACCINE_DOSE_MAPPINGS.dig(
+      vaccination_record.vaccine.brand,
+      vaccination_record.dose_sequence.to_s
+    ) ||
+      "#{vaccination_record.vaccine.brand} " \
+        "Part #{vaccination_record.dose_sequence}"
+  end
+
+  def reason(vaccination_record)
+    case vaccination_record.dose_sequence
+    when 1, nil
+      "Routine"
+    else
+      "At Risk"
+    end
+  end
+
+  # TODO: These mappings are valid for Hertforshire, but may not be correct for
+  #       other SAIS teams. We'll need to check these are correct with new SAIS
+  #       teams.
+  def site(vaccination_record)
+    return if vaccination_record.not_administered?
+
+    DELIVERY_SITE_MAPPINGS.fetch(vaccination_record.delivery_site)
+  end
+end
diff --git a/app/models/vaccination_report.rb b/app/models/vaccination_report.rb
index aa04ebb6fc..6cd04fca6e 100644
--- a/app/models/vaccination_report.rb
+++ b/app/models/vaccination_report.rb
@@ -4,12 +4,18 @@ class VaccinationReport
   include RequestSessionPersistable
   include WizardStepConcern
 
-  FILE_FORMATS = %w[careplus mavis].freeze
-
   def self.request_session_key
     "vaccination_report"
   end
 
+  def self.file_formats(programme)
+    %w[careplus mavis].tap do
+      if Flipper.enabled?(:systm_one_exporter) && programme.hpv?
+        it << "systm_one"
+      end
+    end
+  end
+
   attribute :date_from, :date
   attribute :date_to, :date
   attribute :file_format, :string
@@ -20,7 +26,10 @@ def wizard_steps
   end
 
   on_wizard_step :file_format, exact: true do
-    validates :file_format, inclusion: { in: FILE_FORMATS }
+    validates :file_format,
+              inclusion: {
+                in: -> { VaccinationReport.file_formats(it.programme) }
+              }
   end
 
   def programme
@@ -57,7 +66,8 @@ def csv_filename
   def exporter_class
     {
       careplus: Reports::CareplusExporter,
-      mavis: Reports::ProgrammeVaccinationsExporter
+      mavis: Reports::ProgrammeVaccinationsExporter,
+      systm_one: Reports::SystmOneExporter
     }.fetch(file_format.to_sym)
   end
 
diff --git a/app/views/vaccination_reports/file_format.html.erb b/app/views/vaccination_reports/file_format.html.erb
index 79f125300d..2bc12f55ea 100644
--- a/app/views/vaccination_reports/file_format.html.erb
+++ b/app/views/vaccination_reports/file_format.html.erb
@@ -8,7 +8,7 @@
 <%= form_with model: @vaccination_report, url: wizard_path, method: :put do |f| %>
   <%= f.govuk_error_summary %>
 
-  <%= f.govuk_collection_radio_buttons :file_format, VaccinationReport::FILE_FORMATS, :itself, legend: { text: title, size: "l", tag: "h1" }, caption: { text: @programme.name } %>
+  <%= f.govuk_collection_radio_buttons :file_format, VaccinationReport.file_formats(@programme), :itself, legend: { text: title, size: "l", tag: "h1" }, caption: { text: @programme.name } %>
 
   <%= f.govuk_submit %>
 <% end %>
diff --git a/config/locales/helpers.en.yml b/config/locales/helpers.en.yml
index f36f5c7747..63cf2c2f2f 100644
--- a/config/locales/helpers.en.yml
+++ b/config/locales/helpers.en.yml
@@ -21,3 +21,4 @@ en:
         file_format_options:
           careplus: CarePlus
           mavis: CSV
+          systm_one: SystmOne
diff --git a/db/seeds.rb b/db/seeds.rb
index 579f23cc84..b4278e8170 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -8,7 +8,7 @@
 Faker::Config.locale = "en-GB"
 
 def set_feature_flags
-  %i[dev_tools mesh_jobs cis2].each do |feature_flag|
+  %i[dev_tools mesh_jobs cis2 systm_one_export].each do |feature_flag|
     Flipper.add(feature_flag) unless Flipper.exist?(feature_flag)
   end
 end
diff --git a/spec/features/download_vaccination_reports_spec.rb b/spec/features/download_vaccination_reports_spec.rb
index 51b9030cf3..d0043114d3 100644
--- a/spec/features/download_vaccination_reports_spec.rb
+++ b/spec/features/download_vaccination_reports_spec.rb
@@ -31,6 +31,35 @@
     then_i_download_a_mavis_file
   end
 
+  scenario "Download in SystmOne format" do
+    given_an_hpv_programme_is_underway
+    and_an_administered_vaccination_record_exists
+    and_systm_one_export_is_enabled
+
+    when_i_go_to_the_programme
+    and_i_click_on_download_vaccination_report
+    then_i_see_the_dates_page
+
+    when_i_enter_some_dates
+    then_i_see_the_file_format_page
+
+    when_i_choose_systm_one
+    then_i_download_a_systm_one_file
+  end
+
+  scenario "SystmOne disabled" do
+    given_an_hpv_programme_is_underway
+    and_an_administered_vaccination_record_exists
+
+    when_i_go_to_the_programme
+    and_i_click_on_download_vaccination_report
+    then_i_see_the_dates_page
+
+    when_i_enter_some_dates
+    then_i_see_the_file_format_page
+    and_systm_one_export_is_disabled
+  end
+
   def given_an_hpv_programme_is_underway
     @organisation = create(:organisation, :with_one_nurse)
     @programme = create(:programme, :hpv, organisations: [@organisation])
@@ -66,6 +95,10 @@ def and_an_administered_vaccination_record_exists
     )
   end
 
+  def and_systm_one_export_is_enabled
+    Flipper.enable(:systm_one_exporter)
+  end
+
   def when_i_go_to_the_programme
     sign_in @organisation.users.first
     visit programme_path(@programme)
@@ -109,6 +142,11 @@ def when_i_choose_mavis
     click_on "Continue"
   end
 
+  def when_i_choose_systm_one
+    choose "SystmOne"
+    click_on "Continue"
+  end
+
   def then_i_download_a_careplus_file
     expect(page.status_code).to eq(200)
 
@@ -124,4 +162,16 @@ def then_i_download_a_mavis_file
       "ORGANISATION_CODE,SCHOOL_URN,SCHOOL_NAME,CARE_SETTING,CLINIC_NAME,PERSON_FORENAME,PERSON_SURNAME"
     )
   end
+
+  def then_i_download_a_systm_one_file
+    expect(page.status_code).to eq(200)
+
+    expect(page).to have_content(
+      "Practice code,NHS number,Surname,Middle name,Forename,Gender,Date of Birth,House name,House number and road,Town"
+    )
+  end
+
+  def and_systm_one_export_is_disabled
+    expect(page).not_to have_selector("SystmOne")
+  end
 end
diff --git a/spec/lib/reports/systm_one_exporter_spec.rb b/spec/lib/reports/systm_one_exporter_spec.rb
new file mode 100644
index 0000000000..c1288ce200
--- /dev/null
+++ b/spec/lib/reports/systm_one_exporter_spec.rb
@@ -0,0 +1,223 @@
+# frozen_string_literal: true
+
+describe Reports::SystmOneExporter do
+  subject(:csv_row) { parsed_csv.first }
+
+  before { vaccination_record }
+
+  let(:csv) do
+    described_class.call(
+      organisation:,
+      programme:,
+      start_date: 1.month.ago.to_date,
+      end_date: Date.current
+    )
+  end
+  let(:programme) { create(:programme, :hpv, organisations: [organisation]) }
+  let(:organisation) { create(:organisation, ods_code: "ABC123") }
+  let(:location) { create(:school) }
+  let(:session) do
+    create(:session, organisation:, programmes: [programme], location:)
+  end
+  let(:patient) { create(:patient) }
+  let(:vaccination_record) do
+    create(
+      :vaccination_record,
+      programme:,
+      patient:,
+      session:,
+      performed_at: 2.weeks.ago
+    )
+  end
+  let(:parsed_csv) { CSV.parse(csv, headers: true) }
+
+  it "includes the patient and vaccination details" do
+    expect(parsed_csv.first.to_h).to eq(
+      {
+        "Practice code" => location.urn,
+        "NHS number" => vaccination_record.patient.nhs_number,
+        "Surname" => vaccination_record.patient.family_name,
+        "Middle name" => "",
+        "Forename" => vaccination_record.patient.given_name,
+        "Gender" => "U",
+        "Date of Birth" =>
+          vaccination_record.patient.date_of_birth.strftime("%d/%m/%Y"),
+        "House name" => vaccination_record.patient.address_line_2,
+        "House number and road" => vaccination_record.patient.address_line_1,
+        "Town" => vaccination_record.patient.address_town,
+        "Postcode" => vaccination_record.patient.address_postcode,
+        "Vaccination" => "Y19a4",
+        "Part" => "",
+        "Admin date" =>
+          vaccination_record.performed_at.to_date.strftime("%d/%m/%Y"),
+        "Batch number" => vaccination_record.batch.name,
+        "Expiry date" => vaccination_record.batch.expiry.strftime("%d/%m/%Y"),
+        "Dose" => vaccination_record.dose_volume_ml.to_s,
+        "Reason" => "Routine",
+        "Site" => "Left deltoid",
+        "Method" => vaccination_record.delivery_method,
+        "Notes" => vaccination_record.notes
+      }
+    )
+  end
+
+  context "no vaccination details" do
+    before { vaccination_record.destroy }
+
+    it { should be_blank }
+  end
+
+  context "with vaccination records outside the date range" do
+    let(:vaccination_record) do
+      create(
+        :vaccination_record,
+        programme:,
+        patient:,
+        session:,
+        created_at: 2.months.ago,
+        updated_at: 2.months.ago,
+        performed_at: 2.months.ago
+      )
+    end
+
+    it { should be_blank }
+  end
+
+  context "with vaccination records that haven't been administered" do
+    let(:vaccination_record) do
+      create(
+        :vaccination_record,
+        :not_administered,
+        programme:,
+        patient:,
+        session:
+      )
+    end
+
+    it { should be_blank }
+  end
+
+  context "with vaccination records updated within the date range do" do
+    let(:vaccination_record) do
+      create(
+        :vaccination_record,
+        programme:,
+        patient:,
+        session:,
+        created_at: 2.months.ago,
+        updated_at: 1.day.ago,
+        performed_at: 2.months.ago
+      )
+    end
+
+    it { should_not be_blank }
+  end
+
+  context "with a session in a different organisation" do
+    let(:programme) do
+      create(:programme, :hpv, organisations: [other_organisation])
+    end
+    let(:other_organisation) { create(:organisation, ods_code: "XYZ890") }
+
+    let(:session) do
+      create(
+        :session,
+        organisation: other_organisation,
+        programmes: [programme],
+        location:
+      )
+    end
+
+    it { should be_blank }
+  end
+
+  describe "Practice code field" do
+    subject { csv_row["Practice code"] }
+
+    context "location is a gp clinic" do
+      let(:location) { create(:gp_practice) }
+
+      it { should eq location.ods_code }
+    end
+  end
+
+  describe "Gender field" do
+    subject { csv_row["Gender"] }
+
+    context "gender_code is male" do
+      let(:patient) { create(:patient, gender_code: :male) }
+
+      it { should eq "M" }
+    end
+
+    context "gender_code is female" do
+      let(:patient) { create(:patient, gender_code: :female) }
+
+      it { should eq "F" }
+    end
+
+    context "gender_code is not specified" do
+      let(:patient) { create(:patient, gender_code: :not_specified) }
+
+      it { should eq "U" }
+    end
+  end
+
+  describe "Vaccination field" do
+    subject { csv_row["Vaccination"] }
+
+    let(:vaccination_record) do
+      create(
+        :vaccination_record,
+        programme:,
+        patient:,
+        session:,
+        performed_at: 2.weeks.ago,
+        vaccine:,
+        dose_sequence:
+      )
+    end
+
+    context "HPV Gardasil 9 dose 2" do
+      let(:vaccine) { Vaccine.find_by(brand: "Gardasil 9") }
+      let(:dose_sequence) { 2 }
+
+      it { should eq "Y19a5" }
+    end
+
+    context "HPV Gardasil 9 dose 3" do
+      let(:vaccine) { Vaccine.find_by(brand: "Gardasil 9") }
+      let(:dose_sequence) { 3 }
+
+      it { should eq "Y19a6" }
+    end
+
+    context "unknown vaccine and no dose sequence" do
+      let(:vaccine) { create(:vaccine, :fluad_tetra) }
+      let(:dose_sequence) { 1 }
+
+      it { should eq "Fluad Tetra - aQIV Part 1" }
+    end
+  end
+
+  describe "Site field" do
+    subject { csv_row["Site"] }
+
+    let(:vaccination_record) do
+      create(
+        :vaccination_record,
+        programme:,
+        patient:,
+        session:,
+        performed_at: 2.weeks.ago,
+        delivery_site:
+      )
+    end
+
+    context "left arm lower position" do
+      let(:delivery_site) { "left_arm_lower_position" }
+
+      it { should eq "Left anterior forearm" }
+    end
+  end
+end
diff --git a/spec/models/vaccination_report_spec.rb b/spec/models/vaccination_report_spec.rb
new file mode 100644
index 0000000000..388c127a79
--- /dev/null
+++ b/spec/models/vaccination_report_spec.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+describe VaccinationReport do
+  describe "file_formats" do
+    subject { described_class.file_formats(programme) }
+
+    context "when hpv and feature is disabled" do
+      before { Flipper.disable(:systm_one_exporter) }
+
+      let(:programme) { create(:programme, :hpv) }
+
+      it { should eq(%w[careplus mavis]) }
+    end
+
+    context "when hpv and feature is enabled" do
+      before { Flipper.enable(:systm_one_exporter) }
+
+      let(:programme) { create(:programme, :hpv) }
+
+      it { should eq(%w[careplus mavis systm_one]) }
+    end
+
+    context "when menacwy and feature is enabled" do
+      before { Flipper.enable(:systm_one_exporter) }
+
+      let(:programme) { create(:programme, :menacwy) }
+
+      it { should eq(%w[careplus mavis]) }
+    end
+  end
+end