diff --git a/playbooks/tox/pre.yaml b/playbooks/tox/pre.yaml
index fde7f6155..69e7def02 100644
--- a/playbooks/tox/pre.yaml
+++ b/playbooks/tox/pre.yaml
@@ -1,5 +1,3 @@
 - hosts: all
   roles:
     - ensure-tox
-    - role: tox-siblings
-      when: tox_install_siblings
diff --git a/roles/tox-siblings/README.rst b/roles/tox-siblings/README.rst
deleted file mode 100644
index e7277a5c0..000000000
--- a/roles/tox-siblings/README.rst
+++ /dev/null
@@ -1,29 +0,0 @@
-Installs python packages from other Zuul repos into a tox environment.
-
-**Role Variables**
-
-.. zuul:rolevar:: zuul_workdir
-   :default: {{ zuul.project.src_dir }}
-
-   Directory to run tox in.
-
-.. zuul:rolevar:: tox_envlist
-   :default: venv
-
-   Which tox environment to run. Defaults to 'venv'.
-
-.. zuul:rolevar:: tox_executable
-   :default: tox
-
-   Location of the tox executable. Defaults to 'tox'.
-
-.. zuul:rolevar:: tox_constraints_file
-
-   Path to a pip constraints file. Will be provided to pip via '-c'
-   argument for any sibling package installations.
-
-.. zuul:rolevar:: tox_install_siblings
-   :default: true
-
-   Flag controlling whether to attempt to install python packages from any
-   other source code repos zuul has checked out. Defaults to True.
diff --git a/roles/tox-siblings/defaults/main.yaml b/roles/tox-siblings/defaults/main.yaml
deleted file mode 100644
index dded4aec3..000000000
--- a/roles/tox-siblings/defaults/main.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
----
-tox_envlist: venv
-tox_executable: tox
-tox_install_siblings: true
-
-zuul_work_dir: "{{ zuul.project.src_dir }}"
diff --git a/roles/tox-siblings/tasks/main.yaml b/roles/tox-siblings/tasks/main.yaml
index fe7b1757a..d9091c52b 100644
--- a/roles/tox-siblings/tasks/main.yaml
+++ b/roles/tox-siblings/tasks/main.yaml
@@ -1,3 +1,3 @@
-- name: Install tox siblings
-  include: siblings.yaml
-  when: tox_install_siblings
+- name: Emit warning message
+  debug:
+    msg: tox-siblings is no longer needed and should be removed
diff --git a/roles/tox-siblings/tasks/siblings.yaml b/roles/tox-siblings/tasks/siblings.yaml
deleted file mode 100644
index 0aa391a87..000000000
--- a/roles/tox-siblings/tasks/siblings.yaml
+++ /dev/null
@@ -1,38 +0,0 @@
-- name: Require tox_envlist variable
-  fail:
-    msg: tox_envlist is required for this role
-  when: tox_envlist is not defined
-
-- name: Check to see if the constraints file exists
-  stat:
-    path: "{{ tox_constraints_file }}"
-    get_checksum: false
-    get_mime: false
-    get_md5: false
-  register: stat_results
-  when: tox_constraints_file is defined
-
-- name: Fail if constraints file is missing
-  when: tox_constraints_file is defined and not stat_results.stat.exists
-  fail:
-    msg: tox_constraints_file is defined but was not found
-
-- name: Record file location
-  set_fact:
-    tox_constraints_env:
-      UPPER_CONSTRAINTS_FILE: "{{ tox_constraints_file }}"
-  when: tox_constraints_file is defined
-
-- name: Run tox without tests
-  command: "{{ tox_executable }} --notest -e{{ tox_envlist }}"
-  args:
-    chdir: "{{ zuul_work_dir }}"
-  environment: "{{ tox_environment|combine(tox_constraints_env|default({})) }}"
-
-# TODO(mordred) handle tox_envlist being a list
-- name: Install any sibling python packages
-  tox_install_sibling_packages:
-    tox_envlist: "{{ tox_envlist }}"
-    tox_constraints_file: "{{ tox_constraints_file | default(omit) }}"
-    project_dir: "{{ zuul_work_dir }}"
-    projects: "{{ zuul.projects | selectattr('required') | list }}"
diff --git a/roles/tox/README.rst b/roles/tox/README.rst
index cf1921e80..40932402b 100644
--- a/roles/tox/README.rst
+++ b/roles/tox/README.rst
@@ -26,6 +26,12 @@ Runs tox for a project
    Path to a pip constraints file. Will be provided to tox via
    UPPER_CONSTRAINTS_FILE environment variable if it exists.
 
+.. zuul:rolevar:: tox_install_siblings
+   :default: true
+
+   Flag controlling whether to attempt to install python packages from any
+   other source code repos zuul has checked out. Defaults to True.
+
 .. zuul:rolevar:: zuul_work_dir
    :default: {{ zuul.project.src_dir }}
 
diff --git a/roles/tox/defaults/main.yaml b/roles/tox/defaults/main.yaml
index f4b08abd2..1178db533 100644
--- a/roles/tox/defaults/main.yaml
+++ b/roles/tox/defaults/main.yaml
@@ -3,5 +3,6 @@ tox_environment: {}
 tox_envlist: venv
 tox_executable: tox
 tox_extra_args: -vv
+tox_install_siblings: true
 
 zuul_work_dir: "{{ zuul.project.src_dir }}"
diff --git a/roles/tox-siblings/library/tox_install_sibling_packages.py b/roles/tox/library/tox_install_sibling_packages.py
similarity index 100%
rename from roles/tox-siblings/library/tox_install_sibling_packages.py
rename to roles/tox/library/tox_install_sibling_packages.py
diff --git a/roles/tox/tasks/main.yaml b/roles/tox/tasks/main.yaml
index fe899037b..b1f464fb8 100644
--- a/roles/tox/tasks/main.yaml
+++ b/roles/tox/tasks/main.yaml
@@ -5,18 +5,27 @@
 
 - name: Check to see if the constraints file exists
   stat:
-    path: "{{ tox_constraints_file|default('missing') }}"
+    path: "{{ tox_constraints_file }}"
     get_checksum: false
     get_mime: false
     get_md5: false
   register: stat_results
   when: tox_constraints_file is defined
 
+- name: Fail if constraints file is missing
+  when: tox_constraints_file is defined and not stat_results.stat.exists
+  fail:
+    msg: tox_constraints_file is defined but was not found
+
 - name: Record file location
   set_fact:
     tox_constraints_env:
       UPPER_CONSTRAINTS_FILE: "{{ tox_constraints_file }}"
-  when: not stat_results|skipped and stat_results.stat.exists
+  when: tox_constraints_file is defined
+
+- name: Install tox siblings
+  include: siblings.yaml
+  when: tox_install_siblings
 
 - name: Emit tox command
   debug:
diff --git a/roles/tox/tasks/siblings.yaml b/roles/tox/tasks/siblings.yaml
new file mode 100644
index 000000000..84c43cd73
--- /dev/null
+++ b/roles/tox/tasks/siblings.yaml
@@ -0,0 +1,13 @@
+- name: Run tox without tests
+  command: "{{ tox_executable }} --notest -e{{ tox_envlist }}"
+  args:
+    chdir: "{{ zuul_work_dir }}"
+  environment: "{{ tox_environment|combine(tox_constraints_env|default({})) }}"
+
+# TODO(mordred) handle tox_envlist being a list
+- name: Install any sibling python packages
+  tox_install_sibling_packages:
+    tox_envlist: "{{ tox_envlist }}"
+    tox_constraints_file: "{{ tox_constraints_file | default(omit) }}"
+    project_dir: "{{ zuul_work_dir }}"
+    projects: "{{ zuul.projects | selectattr('required') | list }}"