diff --git a/doc/source/user/config.rst b/doc/source/user/config.rst
index fa874a9..3ea20ab 100644
--- a/doc/source/user/config.rst
+++ b/doc/source/user/config.rst
@@ -658,8 +658,17 @@
 
       * In the case of a job variant defined within a
         :ref:`project-template`, if no branch specifier appears, the
-        implied branch specifier for the :ref:`project` definition which
-        uses the project-template will be used.
+        implied branch containing the project-template definition is
+        used as an implied branch specifier.  This means that
+        definitions of the same project-template on different branches
+        may run different jobs.
+
+        When that project-template is used by a :ref:`project`
+        definition within a :term:`untrusted-project`, the branch
+        containing that project definition is combined with the branch
+        specifier of the project-template.  This means it is possible
+        for a project to use a template on one branch, but not on
+        another.
 
       This allows for the very simple and expected workflow where if a
       project defines a job on the ``master`` branch with no branch
diff --git a/tests/fixtures/config/branch-templates/git/project-config/zuul.yaml b/tests/fixtures/config/branch-templates/git/project-config/zuul.yaml
new file mode 100644
index 0000000..ce08877
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/git/project-config/zuul.yaml
@@ -0,0 +1,26 @@
+- pipeline:
+    name: check
+    manager: independent
+    trigger:
+      gerrit:
+        - event: patchset-created
+    success:
+      gerrit:
+        Verified: 1
+    failure:
+      gerrit:
+        Verified: -1
+
+- job:
+    name: base
+    parent: null
+
+- project:
+    name: project-config
+    check:
+      jobs: []
+
+- project:
+    name: puppet-integration
+    check:
+      jobs: []
diff --git a/tests/fixtures/config/branch-templates/git/puppet-integration/.zuul.yaml b/tests/fixtures/config/branch-templates/git/puppet-integration/.zuul.yaml
new file mode 100644
index 0000000..dfea632
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/git/puppet-integration/.zuul.yaml
@@ -0,0 +1,25 @@
+- job:
+    name: puppet-unit-base
+    run: playbooks/run-unit-tests.yaml
+
+- job:
+    name: puppet-unit-3.8
+    parent: puppet-unit-base
+    branches: ^(stable/(newton|ocata)).*$
+    vars:
+      puppet_gem_version: 3.8
+
+- job:
+    name: puppet-something
+    run: playbooks/run-unit-tests.yaml
+
+- project-template:
+    name: puppet-unit
+    check:
+      jobs:
+        - puppet-unit-3.8
+
+- project:
+    name: puppet-integration
+    templates:
+      - puppet-unit
diff --git a/tests/fixtures/config/branch-templates/git/puppet-integration/README b/tests/fixtures/config/branch-templates/git/puppet-integration/README
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/git/puppet-integration/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/branch-templates/git/puppet-integration/playbooks/run-unit-tests.yaml b/tests/fixtures/config/branch-templates/git/puppet-integration/playbooks/run-unit-tests.yaml
new file mode 100644
index 0000000..f679dce
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/git/puppet-integration/playbooks/run-unit-tests.yaml
@@ -0,0 +1,2 @@
+- hosts: all
+  tasks: []
diff --git a/tests/fixtures/config/branch-templates/git/puppet-tripleo/.zuul.yaml b/tests/fixtures/config/branch-templates/git/puppet-tripleo/.zuul.yaml
new file mode 100644
index 0000000..4be8146
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/git/puppet-tripleo/.zuul.yaml
@@ -0,0 +1,4 @@
+- project:
+    name: puppet-tripleo
+    templates:
+      - puppet-unit
diff --git a/tests/fixtures/config/branch-templates/git/puppet-tripleo/README b/tests/fixtures/config/branch-templates/git/puppet-tripleo/README
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/git/puppet-tripleo/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/branch-templates/main.yaml b/tests/fixtures/config/branch-templates/main.yaml
new file mode 100644
index 0000000..f7677a3
--- /dev/null
+++ b/tests/fixtures/config/branch-templates/main.yaml
@@ -0,0 +1,9 @@
+- tenant:
+    name: tenant-one
+    source:
+      gerrit:
+        config-projects:
+          - project-config
+        untrusted-projects:
+          - puppet-integration
+          - puppet-tripleo
diff --git a/tests/unit/test_v3.py b/tests/unit/test_v3.py
index c04604d..e2da808 100755
--- a/tests/unit/test_v3.py
+++ b/tests/unit/test_v3.py
@@ -157,6 +157,115 @@
         self.assertIn('Unable to modify final job', A.messages[0])
 
 
+class TestBranchTemplates(ZuulTestCase):
+    tenant_config_file = 'config/branch-templates/main.yaml'
+
+    def test_template_removal_from_branch(self):
+        # Test that a template can be removed from one branch but not
+        # another.
+        # This creates a new branch with a copy of the config in master
+        self.create_branch('puppet-integration', 'stable/newton')
+        self.create_branch('puppet-integration', 'stable/ocata')
+        self.create_branch('puppet-tripleo', 'stable/newton')
+        self.create_branch('puppet-tripleo', 'stable/ocata')
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-integration', 'stable/newton'))
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-integration', 'stable/ocata'))
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-tripleo', 'stable/newton'))
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-tripleo', 'stable/ocata'))
+        self.waitUntilSettled()
+
+        in_repo_conf = textwrap.dedent(
+            """
+            - project:
+                name: puppet-tripleo
+                check:
+                  jobs:
+                    - puppet-something
+            """)
+
+        file_dict = {'.zuul.yaml': in_repo_conf}
+        A = self.fake_gerrit.addFakeChange('puppet-tripleo', 'stable/newton',
+                                           'A', files=file_dict)
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.assertHistory([
+            dict(name='puppet-something', result='SUCCESS', changes='1,1')])
+
+    def test_template_change_on_branch(self):
+        # Test that the contents of a template can be changed on one
+        # branch without affecting another.
+
+        # This creates a new branch with a copy of the config in master
+        self.create_branch('puppet-integration', 'stable/newton')
+        self.create_branch('puppet-integration', 'stable/ocata')
+        self.create_branch('puppet-tripleo', 'stable/newton')
+        self.create_branch('puppet-tripleo', 'stable/ocata')
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-integration', 'stable/newton'))
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-integration', 'stable/ocata'))
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-tripleo', 'stable/newton'))
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'puppet-tripleo', 'stable/ocata'))
+        self.waitUntilSettled()
+
+        in_repo_conf = textwrap.dedent("""
+            - job:
+                name: puppet-unit-base
+                run: playbooks/run-unit-tests.yaml
+
+            - job:
+                name: puppet-unit-3.8
+                parent: puppet-unit-base
+                branches: ^(stable/(newton|ocata)).*$
+                vars:
+                  puppet_gem_version: 3.8
+
+            - job:
+                name: puppet-something
+                run: playbooks/run-unit-tests.yaml
+
+            - project-template:
+                name: puppet-unit
+                check:
+                  jobs:
+                    - puppet-something
+
+            - project:
+                name: puppet-integration
+                templates:
+                  - puppet-unit
+        """)
+
+        file_dict = {'.zuul.yaml': in_repo_conf}
+        A = self.fake_gerrit.addFakeChange('puppet-integration',
+                                           'stable/newton',
+                                           'A', files=file_dict)
+        B = self.fake_gerrit.addFakeChange('puppet-tripleo',
+                                           'stable/newton',
+                                           'B')
+        B.data['commitMessage'] = '%s\n\nDepends-On: %s\n' % (
+            B.subject, A.data['id'])
+        self.fake_gerrit.addEvent(B.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.assertHistory([
+            dict(name='puppet-something', result='SUCCESS',
+                 changes='1,1 2,1')])
+
+
 class TestBranchVariants(ZuulTestCase):
     tenant_config_file = 'config/branch-variants/main.yaml'
 
diff --git a/zuul/model.py b/zuul/model.py
index b027c53..5d8d271 100644
--- a/zuul/model.py
+++ b/zuul/model.py
@@ -948,6 +948,28 @@
             matchers.append(change_matcher.BranchMatcher(branch))
         self.branch_matcher = change_matcher.MatchAny(matchers)
 
+    def getSimpleBranchMatcher(self):
+        # If the job has a simple branch matcher, return it; otherwise None.
+        if not self.branch_matcher:
+            return None
+        m = self.branch_matcher
+        if not isinstance(m, change_matcher.AbstractMatcherCollection):
+            return None
+        if len(m.matchers) != 1:
+            return None
+        m = m.matchers[0]
+        if not isinstance(m, change_matcher.BranchMatcher):
+            return None
+        return m._regex
+
+    def addBranchMatcher(self, branch):
+        # Add a branch matcher that combines as a boolean *and* with
+        # existing branch matchers, if any.
+        matchers = [change_matcher.BranchMatcher(branch)]
+        if self.branch_matcher:
+            matchers.append(self.branch_matcher)
+        self.branch_matcher = change_matcher.MatchAll(matchers)
+
     def updateVariables(self, other_vars):
         v = copy.deepcopy(self.variables)
         Job._deepUpdate(v, other_vars)
@@ -1097,9 +1119,26 @@
         for jobname, jobs in other.jobs.items():
             joblist = self.jobs.setdefault(jobname, [])
             for job in jobs:
-                if not job.branch_matcher and implied_branch:
-                    job = job.copy()
-                    job.setBranchMatcher([implied_branch])
+                if implied_branch:
+                    # If setting an implied branch and the current
+                    # branch matcher is a simple match for a different
+                    # branch, then simply do not add this job.  If it
+                    # is absent, set it to the implied branch.
+                    # Otherwise, combine it with the implied branch to
+                    # ensure that it still only affects this branch
+                    # (whatever else it may do).
+                    simple_branch = job.getSimpleBranchMatcher()
+                    if simple_branch and simple_branch != implied_branch:
+                        # Job is for a different branch, don't add it.
+                        continue
+                    if not simple_branch:
+                        # The branch matcher could be complex, or
+                        # missing.  Add our implied matcher.
+                        job = job.copy()
+                        job.addBranchMatcher(implied_branch)
+                    # Otherwise we have a simple branch matcher which
+                    # is the same as our implied branch, the job can
+                    # be added as-is.
                 if job not in joblist:
                     joblist.append(job)