diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 074e06e9c..74ccafe48 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -1329,6 +1329,29 @@ matrix_backup_borg_systemd_required_services_list: |
 # /matrix-backup-borg
 #
 ######################################################################
+######################################################################
+#
+# matrix-cactus-comments
+#
+######################################################################
+
+matrix_cactus_comments_enabled: false
+
+matrix_cactus_comments_container_image_self_build: "{{ matrix_architecture not in ['amd64', 'arm32', 'arm64'] }}"
+
+matrix_corporal_systemd_required_services_list: |
+  {{
+    (['docker.service'])
+    +
+    (['matrix-' + matrix_homeserver_implementation + '.service'])
+  }}
+matrix_cactus_comments_homeserver_url: {{ matrix_homeserver_url }}
+
+######################################################################
+#
+# /matrix-cactus-comments
+#
+######################################################################
 
 ######################################################################
 #
diff --git a/roles/matrix-cactus-comments/defaults/main.yml b/roles/matrix-cactus-comments/defaults/main.yml
new file mode 100644
index 000000000..b925b9efa
--- /dev/null
+++ b/roles/matrix-cactus-comments/defaults/main.yml
@@ -0,0 +1,29 @@
+---
+# Cactus Comments is a federated comment system built on Matrix
+
+matrix_cactus_comments_enabled: true
+matrix_cactus_comments_app_service_config_file: "{{ matrix_cactus_comments_base_path }}/cactus_appservice.yaml"
+matrix_synapse_app_service_config_files: {{ matrix_cactus_comments_app_service_config_file }}
+
+matrix_cactus_comments_as_token: ''
+matrix_cactus_comments_hs_token: ''
+matrix_cactus_comments_homeserver_url: ''
+matrix_cactus_comments_user_id: cactus-comments
+
+matrix_cactus_comments_version: latest
+matrix_cactus_comments_docker_image: "{{ matrix_container_global_registry_prefix }}cactuscomments/cactus-appservice:{{ matrix_cactus_comments_version }}"
+matrix_cactus_comments_docker_image_force_pull: "{{ matrix_cactus_comments_docker_image.endswith(':latest') }}"
+
+matrix_cactus_comments_base_path: "{{ matrix_base_data_path }}/cactus-comments"
+matrix_cactus_comments_config_path: "{{ matrix_cactus_comments_base_path }}/config"
+
+
+# List of systemd services that matrix-cactus-comments.service depends on
+matrix_bot_cactus_comments_systemd_required_services_list: ['docker.service']
+
+# List of systemd services that matrix-cactus-comments.service wants
+matrix_bot_cactus_comments_systemd_wanted_services_list: []
+
+# A list of extra arguments to pass to the container
+matrix_cactus_comments_container_extra_arguments: []
+
diff --git a/roles/matrix-cactus-comments/tasks/init.yml b/roles/matrix-cactus-comments/tasks/init.yml
new file mode 100644
index 000000000..91b1f095d
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/init.yml
@@ -0,0 +1,5 @@
+---
+
+- ansible.builtin.set_fact:
+    matrix_systemd_services_list: "{{ matrix_systemd_services_list + ['matrix-bot-matrix-registration-bot.service'] }}"
+  when: matrix_bot_matrix_registration_bot_enabled | bool
diff --git a/roles/matrix-cactus-comments/tasks/main.yml b/roles/matrix-cactus-comments/tasks/main.yml
new file mode 100644
index 000000000..cc162e991
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/main.yml
@@ -0,0 +1,23 @@
+---
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/init.yml"
+  tags:
+    - always
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/validate_config.yml"
+  when: "run_setup | bool and matrix_bot_matrix_registration_bot_enabled | bool"
+  tags:
+    - setup-all
+    - setup-bot-matrix-registration-bot
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/setup_install.yml"
+  when: "run_setup | bool and matrix_bot_matrix_registration_bot_enabled | bool"
+  tags:
+    - setup-all
+    - setup-bot-matrix-registration-bot
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/setup_uninstall.yml"
+  when: "run_setup | bool and not matrix_bot_matrix_registration_bot_enabled | bool"
+  tags:
+    - setup-all
+    - setup-bot-matrix-registration-bot
diff --git a/roles/matrix-cactus-comments/tasks/setup_install.yml b/roles/matrix-cactus-comments/tasks/setup_install.yml
new file mode 100644
index 000000000..d4522321e
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/setup_install.yml
@@ -0,0 +1,74 @@
+---
+
+- name: Ensure matrix-registration-bot paths exist
+  ansible.builtin.file:
+    path: "{{ item.path }}"
+    state: directory
+    mode: 0750
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  with_items:
+    - {path: "{{ matrix_bot_matrix_registration_bot_config_path }}", when: true}
+    - - {path: "{{ matrix_bot_matrix_registration_bot_data_path }}", when: true}
+    - {path: "{{ matrix_bot_matrix_registration_bot_docker_src_files_path }}", when: true}
+  when: "item.when | bool"
+
+- name: Ensure matrix-registration-bot configuration file created
+  ansible.builtin.template:
+    src: "{{ role_path }}/templates/config/config.yml.j2"
+    dest: "{{ matrix_bot_matrix_registration_bot_config_path }}/config.yml"
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+    mode: 0640
+
+- name: Ensure matrix-registration-bot image is pulled
+  docker_image:
+    name: "{{ matrix_bot_matrix_registration_bot_docker_image }}"
+    source: "{{ 'pull' if ansible_version.major > 2 or ansible_version.minor > 7 else omit }}"
+    force_source: "{{ matrix_bot_matrix_registration_bot_docker_image_force_pull if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
+    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_bot_matrix_registration_bot_docker_image_force_pull }}"
+  when: "not matrix_bot_matrix_registration_bot_container_image_self_build | bool"
+  register: result
+  retries: "{{ matrix_container_retries_count }}"
+  delay: "{{ matrix_container_retries_delay }}"
+  until: result is not failed
+
+- name: Ensure matrix-registration-bot repository is present on self-build
+  ansible.builtin.git:
+    repo: "{{ matrix_bot_matrix_registration_bot_docker_repo }}"
+    version: "{{ matrix_bot_matrix_registration_bot_docker_repo_version }}"
+    dest: "{{ matrix_bot_matrix_registration_bot_docker_src_files_path }}"
+    force: "yes"
+  become: true
+  become_user: "{{ matrix_user_username }}"
+  register: matrix_bot_matrix_registration_bot_git_pull_results
+  when: "matrix_bot_matrix_registration_bot_container_image_self_build | bool"
+
+- name: Ensure matrix-registration-bot image is built
+  docker_image:
+    name: "{{ matrix_bot_matrix_registration_bot_docker_image }}"
+    source: build
+    force_source: "{{ matrix_bot_matrix_registration_bot_git_pull_results.changed if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
+    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_mailer_git_pull_results.changed }}"
+    build:
+      dockerfile: Dockerfile
+      path: "{{ matrix_bot_matrix_registration_bot_docker_src_files_path }}"
+      pull: true
+  when: "matrix_bot_matrix_registration_bot_container_image_self_build | bool"
+
+- name: Ensure matrix-bot-matrix-registration-bot.service installed
+  ansible.builtin.template:
+    src: "{{ role_path }}/templates/systemd/matrix-bot-matrix-registration-bot.service.j2"
+    dest: "{{ matrix_systemd_path }}/matrix-bot-matrix-registration-bot.service"
+    mode: 0644
+  register: matrix_bot_matrix_registration_bot_systemd_service_result
+
+- name: Ensure systemd reloaded after matrix-bot-matrix-registration-bot.service installation
+  ansible.builtin.service:
+    daemon_reload: true
+  when: "matrix_bot_matrix_registration_bot_systemd_service_result.changed | bool"
+
+- name: Ensure matrix-bot-matrix-registration-bot.service restarted, if necessary
+  ansible.builtin.service:
+    name: "matrix-bot-matrix-registration-bot.service"
+    state: restarted
diff --git a/roles/matrix-cactus-comments/tasks/setup_uninstall.yml b/roles/matrix-cactus-comments/tasks/setup_uninstall.yml
new file mode 100644
index 000000000..426eefc10
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/setup_uninstall.yml
@@ -0,0 +1,36 @@
+---
+
+- name: Check existence of matrix-matrix-registration-bot service
+  ansible.builtin.stat:
+    path: "{{ matrix_systemd_path }}/matrix-bot-matrix-registration-bot.service"
+  register: matrix_bot_matrix_registration_bot_service_stat
+
+- name: Ensure matrix-matrix-registration-bot is stopped
+  ansible.builtin.service:
+    name: matrix-bot-matrix-registration-bot
+    state: stopped
+    enabled: false
+    daemon_reload: true
+  register: stopping_result
+  when: "matrix_bot_matrix_registration_bot_service_stat.stat.exists | bool"
+
+- name: Ensure matrix-bot-matrix-registration-bot.service doesn't exist
+  ansible.builtin.file:
+    path: "{{ matrix_systemd_path }}/matrix-bot-matrix-registration-bot.service"
+    state: absent
+  when: "matrix_bot_matrix_registration_bot_service_stat.stat.exists | bool"
+
+- name: Ensure systemd reloaded after matrix-bot-matrix-registration-bot.service removal
+  ansible.builtin.service:
+    daemon_reload: true
+  when: "matrix_bot_matrix_registration_bot_service_stat.stat.exists | bool"
+
+- name: Ensure Matrix matrix-registration-bot paths don't exist
+  ansible.builtin.file:
+    path: "{{ matrix_bot_matrix_registration_bot_base_path }}"
+    state: absent
+
+- name: Ensure matrix-registration-bot Docker image doesn't exist
+  docker_image:
+    name: "{{ matrix_bot_matrix_registration_bot_docker_image }}"
+    state: absent
diff --git a/roles/matrix-cactus-comments/tasks/validate_config.yml b/roles/matrix-cactus-comments/tasks/validate_config.yml
new file mode 100644
index 000000000..094a203df
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/validate_config.yml
@@ -0,0 +1,10 @@
+---
+
+- name: Fail if required settings not defined
+  ansible.builtin.fail:
+    msg: >-
+      You need to define a required configuration setting (`{{ item }}`).
+  when: "vars[item] == ''"
+  with_items:
+    - "matrix_cactus_comments_as_token"
+    - "matrix_cactus_comments_hs_token"
diff --git a/roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2 b/roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2
new file mode 100644
index 000000000..b41ceba19
--- /dev/null
+++ b/roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2
@@ -0,0 +1,19 @@
+# A unique, user-defined ID of the application service which will never change.
+id: "Cactus Comments"
+
+# Where the cactus-appservice is hosted:
+url: "http://cactus:5000"
+
+# Unique tokens used to authenticate requests between our service and the
+# homeserver (and the other way). Use the sha256 hashes of something random.
+# CHANGE THESE VALUES.
+as_token: "a2d7789eedb3c5076af0864f4af7bef77b1f250ac4e454c373c806876e939cca"
+hs_token: "b3b05236568ab46f0d98a978936c514eac93d8f90e6d5cd3895b3db5bb8d788b"
+
+# User associated with our service. In this case "@cactusbot:example.com"
+sender_localpart: "cactusbot"
+
+namespaces:
+  aliases:
+    - exclusive: true
+      regex: "#comments_.*"
diff --git a/roles/matrix-cactus-comments/templates/env.j2 b/roles/matrix-cactus-comments/templates/env.j2
new file mode 100644
index 000000000..21c395e1d
--- /dev/null
+++ b/roles/matrix-cactus-comments/templates/env.j2
@@ -0,0 +1,6 @@
+CACTUS_HS_TOKEN=b3b05236568ab46f0d98a978936c514eac93d8f90e6d5cd3895b3db5bb8d788b
+CACTUS_AS_TOKEN=a2d7789eedb3c5076af0864f4af7bef77b1f250ac4e454c373c806876e939cca
+CACTUS_HOMESERVER_URL=http://synapse:8008
+CACTUS_USER_ID=@cactusbot:example.com
+
+{{ matrix_cactus_comments_environment_variables_extension }}
diff --git a/roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2 b/roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2
new file mode 100644
index 000000000..cbbb2d390
--- /dev/null
+++ b/roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2
@@ -0,0 +1,37 @@
+#jinja2: lstrip_blocks: "True"
+[Unit]
+Description=Cactus Comments
+{% for service in matrix_bot_matrix_registration_bot_systemd_required_services_list %}
+Requires={{ service }}
+After={{ service }}
+{% endfor %}
+{% for service in matrix_bot_matrix_registration_bot_systemd_wanted_services_list %}
+Wants={{ service }}
+{% endfor %}
+DefaultDependencies=no
+
+[Service]
+Type=simple
+Environment="HOME={{ matrix_systemd_unit_home_path }}"
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-bot-matrix-registration-bot 2>/dev/null || true'
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-bot-matrix-registration-bot 2>/dev/null || true'
+
+ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-bot-matrix-registration-bot \
+			--log-driver=none \
+			--cap-drop=ALL \
+			-e "CONFIG_PATH=/config/config.yml" \
+			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
+			--read-only \
+			--mount type=bind,src={{ matrix_bot_matrix_registration_bot_config_path }},dst=/config,ro \
+			--mount type=bind,src={{ matrix_bot_matrix_registration_bot_data_path }},dst=/data \
+			--network={{ matrix_docker_network }} \
+			{{ matrix_bot_matrix_registration_bot_docker_image }}
+
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-bot-matrix-registration-bot 2>/dev/null || true'
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-bot-matrix-registration-bot 2>/dev/null || true'
+Restart=always
+RestartSec=30
+SyslogIdentifier=matrix-bot-matrix-registration-bot
+
+[Install]
+WantedBy=multi-user.target