diff --git a/doc/source/user/config.rst b/doc/source/user/config.rst
index 76f73c3407..c4f09de5e2 100644
--- a/doc/source/user/config.rst
+++ b/doc/source/user/config.rst
@@ -738,6 +738,12 @@ unless otherwise specified:
   be installed (and therefore referenced from Ansible), the `name`
   attribute may be used to specify an alternate.
 
+  A job automatically has the project in which it is defined added to
+  the roles path if that project appears to contain a role or `roles/`
+  directory.  By default, the project is added to the path under its
+  own name, however, that may be changed by explicitly listing the
+  project in the roles list in the usual way.
+
   .. note:: galaxy roles are not yet implemented
 
   **galaxy**
diff --git a/tests/fixtures/config/implicit-roles/git/common-config/zuul.yaml b/tests/fixtures/config/implicit-roles/git/common-config/zuul.yaml
new file mode 100644
index 0000000000..ba91fb5557
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/common-config/zuul.yaml
@@ -0,0 +1,12 @@
+- pipeline:
+    name: check
+    manager: independent
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        verified: 1
+    failure:
+      gerrit:
+        verified: -1
diff --git a/tests/fixtures/config/implicit-roles/git/org_norole-project/.zuul.yaml b/tests/fixtures/config/implicit-roles/git/org_norole-project/.zuul.yaml
new file mode 100644
index 0000000000..74c8e8ea32
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_norole-project/.zuul.yaml
@@ -0,0 +1,15 @@
+- job:
+    name: implicit-role-fail
+
+- job:
+    name: explicit-role-fail
+    attempts: 1
+    roles:
+      - zuul: org/norole-project
+
+- project:
+    name: org/norole-project
+    check:
+      jobs:
+        - implicit-role-fail
+        - explicit-role-fail
diff --git a/tests/fixtures/config/implicit-roles/git/org_norole-project/README b/tests/fixtures/config/implicit-roles/git/org_norole-project/README
new file mode 100644
index 0000000000..9daeafb986
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_norole-project/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/implicit-roles/git/org_norole-project/playbooks/explicit-role-fail.yaml b/tests/fixtures/config/implicit-roles/git/org_norole-project/playbooks/explicit-role-fail.yaml
new file mode 100644
index 0000000000..f679dceaef
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_norole-project/playbooks/explicit-role-fail.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/implicit-roles/git/org_norole-project/playbooks/implicit-role-fail.yaml b/tests/fixtures/config/implicit-roles/git/org_norole-project/playbooks/implicit-role-fail.yaml
new file mode 100644
index 0000000000..f679dceaef
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_norole-project/playbooks/implicit-role-fail.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/implicit-roles/git/org_role-project/.zuul.yaml b/tests/fixtures/config/implicit-roles/git/org_role-project/.zuul.yaml
new file mode 100644
index 0000000000..42cae95dd7
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_role-project/.zuul.yaml
@@ -0,0 +1,15 @@
+- job:
+    name: implicit-role-ok
+
+- job:
+    name: explicit-role-ok
+    roles:
+      - zuul: org/role-project
+        name: role-name
+
+- project:
+    name: org/role-project
+    check:
+      jobs:
+        - implicit-role-ok
+        - explicit-role-ok
diff --git a/tests/fixtures/config/implicit-roles/git/org_role-project/README b/tests/fixtures/config/implicit-roles/git/org_role-project/README
new file mode 100644
index 0000000000..9daeafb986
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_role-project/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/implicit-roles/git/org_role-project/playbooks/explicit-role-ok.yaml b/tests/fixtures/config/implicit-roles/git/org_role-project/playbooks/explicit-role-ok.yaml
new file mode 100644
index 0000000000..f679dceaef
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_role-project/playbooks/explicit-role-ok.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/implicit-roles/git/org_role-project/playbooks/implicit-role-ok.yaml b/tests/fixtures/config/implicit-roles/git/org_role-project/playbooks/implicit-role-ok.yaml
new file mode 100644
index 0000000000..f679dceaef
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/git/org_role-project/playbooks/implicit-role-ok.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/implicit-roles/git/org_role-project/roles/README b/tests/fixtures/config/implicit-roles/git/org_role-project/roles/README
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/fixtures/config/implicit-roles/main.yaml b/tests/fixtures/config/implicit-roles/main.yaml
new file mode 100644
index 0000000000..d5e481a543
--- /dev/null
+++ b/tests/fixtures/config/implicit-roles/main.yaml
@@ -0,0 +1,9 @@
+- tenant:
+    name: tenant-one
+    source:
+      gerrit:
+        config-projects:
+          - common-config
+        untrusted-projects:
+          - org/norole-project
+          - org/role-project
diff --git a/tests/unit/test_v3.py b/tests/unit/test_v3.py
index 734c45c954..b162469434 100644
--- a/tests/unit/test_v3.py
+++ b/tests/unit/test_v3.py
@@ -716,9 +716,7 @@ class TestProjectKeys(ZuulTestCase):
         self.assertEqual(4096, private_key.key_size)
 
 
-class TestRoles(ZuulTestCase):
-    tenant_config_file = 'config/roles/main.yaml'
-
+class RoleTestCase(ZuulTestCase):
     def _assertRolePath(self, build, playbook, content):
         path = os.path.join(self.test_root, build.uuid,
                             'ansible', playbook, 'ansible.cfg')
@@ -738,6 +736,10 @@ class TestRoles(ZuulTestCase):
                              "Should have no roles_path line in %s" %
                              (playbook,))
 
+
+class TestRoles(RoleTestCase):
+    tenant_config_file = 'config/roles/main.yaml'
+
     def test_role(self):
         # This exercises a proposed change to a role being checked out
         # and used.
@@ -822,6 +824,57 @@ class TestRoles(ZuulTestCase):
             A.messages[-1])
 
 
+class TestImplicitRoles(RoleTestCase):
+    tenant_config_file = 'config/implicit-roles/main.yaml'
+
+    def test_missing_roles(self):
+        # Test implicit and explicit roles for a project which does
+        # not have roles.  The implicit role should be silently
+        # ignored since the project doesn't supply roles, but if a
+        # user declares an explicit role, it should error.
+        self.executor_server.hold_jobs_in_build = True
+        A = self.fake_gerrit.addFakeChange('org/norole-project', 'master', 'A')
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 2)
+        build = self.getBuildByName('implicit-role-fail')
+        self._assertRolePath(build, 'playbook_0', None)
+
+        self.executor_server.hold_jobs_in_build = False
+        self.executor_server.release()
+        self.waitUntilSettled()
+        # The retry_limit doesn't get recorded
+        self.assertHistory([
+            dict(name='implicit-role-fail', result='SUCCESS', changes='1,1'),
+        ])
+
+    def test_roles(self):
+        # Test implicit and explicit roles for a project which does
+        # have roles.  In both cases, we should end up with the role
+        # in the path.  In the explicit case, ensure we end up with
+        # the name we specified.
+        self.executor_server.hold_jobs_in_build = True
+        A = self.fake_gerrit.addFakeChange('org/role-project', 'master', 'A')
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 2)
+        build = self.getBuildByName('implicit-role-ok')
+        self._assertRolePath(build, 'playbook_0', 'role_0')
+
+        build = self.getBuildByName('explicit-role-ok')
+        self._assertRolePath(build, 'playbook_0', 'role_0')
+
+        self.executor_server.hold_jobs_in_build = False
+        self.executor_server.release()
+        self.waitUntilSettled()
+        self.assertHistory([
+            dict(name='implicit-role-ok', result='SUCCESS', changes='1,1'),
+            dict(name='explicit-role-ok', result='SUCCESS', changes='1,1'),
+        ], ordered=False)
+
+
 class TestShadow(ZuulTestCase):
     tenant_config_file = 'config/shadow/main.yaml'
 
diff --git a/zuul/configloader.py b/zuul/configloader.py
index f8e2d15bf5..48d9134bba 100644
--- a/zuul/configloader.py
+++ b/zuul/configloader.py
@@ -425,14 +425,19 @@ class JobParser(object):
 
         # Roles are part of the playbook context so we must establish
         # them earlier than playbooks.
+        roles = []
         if 'roles' in conf:
-            roles = []
             for role in conf.get('roles', []):
                 if 'zuul' in role:
                     r = JobParser._makeZuulRole(tenant, job, role)
                     if r:
                         roles.append(r)
-            job.addRoles(roles)
+        # A job's repo should be an implicit role source for that job,
+        # but not in a project-pipeline variant.
+        if not project_pipeline:
+            r = JobParser._makeImplicitRole(job)
+            roles.insert(0, r)
+        job.addRoles(roles)
 
         for pre_run_name in as_list(conf.get('pre-run')):
             pre_run = model.PlaybookContext(job.source_context,
@@ -554,6 +559,15 @@ class JobParser(object):
                               project.connection_name,
                               project.name)
 
+    @staticmethod
+    def _makeImplicitRole(job):
+        project = job.source_context.project
+        name = project.name.split('/')[-1]
+        return model.ZuulRole(name,
+                              project.connection_name,
+                              project.name,
+                              implicit=True)
+
 
 class ProjectTemplateParser(object):
     log = logging.getLogger("zuul.ProjectTemplateParser")
diff --git a/zuul/executor/server.py b/zuul/executor/server.py
index f291dce9cd..ae362638fe 100644
--- a/zuul/executor/server.py
+++ b/zuul/executor/server.py
@@ -51,6 +51,10 @@ class ExecutorError(Exception):
     pass
 
 
+class RoleNotFoundError(ExecutorError):
+    pass
+
+
 class Watchdog(object):
     def __init__(self, timeout, function, args):
         self.timeout = timeout
@@ -1137,12 +1141,14 @@ class AnsibleJob(object):
         if os.path.isdir(d):
             # This repo has a collection of roles
             if not trusted:
+                self._blockPluginDirs(d)
                 for entry in os.listdir(d):
-                    if os.path.isdir(os.path.join(d, entry)):
-                        self._blockPluginDirs(os.path.join(d, entry))
+                    entry_path = os.path.join(d, entry)
+                    if os.path.isdir(entry_path):
+                        self._blockPluginDirs(entry_path)
             return d
         # It is neither a bare role, nor a collection of roles
-        raise ExecutorError("Unable to find role in %s" % (path,))
+        raise RoleNotFoundError("Unable to find role in %s" % (path,))
 
     def prepareZuulRole(self, jobdir_playbook, role, args, root):
         self.log.debug("Prepare zuul role for %s" % (role,))
@@ -1183,10 +1189,17 @@ class AnsibleJob(object):
             raise ExecutorError("Invalid role name %s", name)
         os.symlink(path, link)
 
-        role_path = self.findRole(link, trusted=jobdir_playbook.trusted)
+        try:
+            role_path = self.findRole(link, trusted=jobdir_playbook.trusted)
+        except RoleNotFoundError:
+            if role['implicit']:
+                self.log.info("Implicit role not found in %s", link)
+                return
+            raise
         if role_path is None:
             # In the case of a bare role, add the containing directory
             role_path = root
+        self.log.debug("Adding role path %s", role_path)
         jobdir_playbook.roles_path.append(role_path)
 
     def prepareAnsibleFiles(self, args):
diff --git a/zuul/model.py b/zuul/model.py
index 1df70dbc06..693b729374 100644
--- a/zuul/model.py
+++ b/zuul/model.py
@@ -702,10 +702,12 @@ class Role(object, metaclass=abc.ABCMeta):
 class ZuulRole(Role):
     """A reference to an ansible role in a Zuul project."""
 
-    def __init__(self, target_name, connection_name, project_name):
+    def __init__(self, target_name, connection_name, project_name,
+                 implicit=False):
         super(ZuulRole, self).__init__(target_name)
         self.connection_name = connection_name
         self.project_name = project_name
+        self.implicit = implicit
 
     def __repr__(self):
         return '<ZuulRole %s %s>' % (self.project_name, self.target_name)
@@ -715,6 +717,8 @@ class ZuulRole(Role):
     def __eq__(self, other):
         if not isinstance(other, ZuulRole):
             return False
+        # Implicit is not consulted for equality so that we can handle
+        # implicit to explicit conversions.
         return (super(ZuulRole, self).__eq__(other) and
                 self.connection_name == other.connection_name and
                 self.project_name == other.project_name)
@@ -725,6 +729,7 @@ class ZuulRole(Role):
         d['type'] = 'zuul'
         d['connection'] = self.connection_name
         d['project'] = self.project_name
+        d['implicit'] = self.implicit
         return d
 
 
@@ -867,11 +872,31 @@ class Job(object):
             self.run = self.implied_run
 
     def addRoles(self, roles):
-        newroles = list(self.roles)
+        newroles = []
+        # Start with a copy of the existing roles, but if any of them
+        # are implicit roles which are identified as explicit in the
+        # new roles list, replace them with the explicit version.
+        changed = False
+        for existing_role in self.roles:
+            if existing_role in roles:
+                new_role = roles[roles.index(existing_role)]
+            else:
+                new_role = None
+            if (new_role and
+                isinstance(new_role, ZuulRole) and
+                isinstance(existing_role, ZuulRole) and
+                existing_role.implicit and not new_role.implicit):
+                newroles.append(new_role)
+                changed = True
+            else:
+                newroles.append(existing_role)
+        # Now add the new roles.
         for role in reversed(roles):
             if role not in newroles:
                 newroles.insert(0, role)
-        self.roles = tuple(newroles)
+                changed = True
+        if changed:
+            self.roles = tuple(newroles)
 
     def updateVariables(self, other_vars):
         v = self.variables