diff --git a/media/commitfest/js/change_tag.js b/media/commitfest/js/change_tag.js
new file mode 100644
index 00000000..ae4c224a
--- /dev/null
+++ b/media/commitfest/js/change_tag.js
@@ -0,0 +1,44 @@
+// An input validator for the color picker. Points out low-contrast tag color
+// choices.
+const input = document.getElementById("id_color");
+input.addEventListener("input", (event) => {
+	// Don't do anything if the color code doesn't pass default validity.
+	input.setCustomValidity("");
+	if (!input.validity.valid) {
+		return;
+	}
+
+	// Break the #rrggbb color code into RGB components.
+	color = parseInt(input.value.substr(1), 16);
+	red = ((color & 0xFF0000) >> 16) / 255.;
+	green = ((color & 0x00FF00) >> 8) / 255.;
+	blue = (color & 0x0000FF) / 255.;
+
+	// Compare the contrast ratio against white. All the magic math comes from
+	// Web Content Accessibility Guidelines (WCAG) 2.2, Technique G18:
+	//
+	//     https://www.w3.org/WAI/WCAG22/Techniques/general/G18.html
+	//
+	function l(val) {
+		if (val <= 0.04045) {
+			return val / 12.92;
+		}
+		return ((val + 0.055) / 1.055) ** 2.4;
+	}
+
+	lum = 0.2126 * l(red) + 0.7152 * l(green) + 0.0722 * l(blue);
+	contrast = (1 + 0.05) / (lum + 0.05);
+
+	// Complain if we're below WCAG 2.2 recommendations.
+	if (contrast < 4.5) {
+		input.setCustomValidity(
+			"Consider choosing a darker color. "
+			+ "(Tag text is small and white.)\n\n"
+		    + "Contrast ratio: " + (Math.trunc(contrast * 10) / 10) + " (< 4.5)"
+		);
+
+		// The admin form uses novalidate, so manually display the browser's
+		// validity popup. (The user can still ignore it if desired.)
+		input.reportValidity();
+	}
+});
diff --git a/pgcommitfest/commitfest/admin.py b/pgcommitfest/commitfest/admin.py
index 8c8d62e5..1cfa4bc7 100644
--- a/pgcommitfest/commitfest/admin.py
+++ b/pgcommitfest/commitfest/admin.py
@@ -1,8 +1,10 @@
 from django.contrib import admin
+from django.forms import widgets
 
 from .models import (
     CfbotBranch,
     CfbotTask,
+    ColorField,
     CommitFest,
     Committer,
     MailThread,
@@ -10,6 +12,7 @@
     Patch,
     PatchHistory,
     PatchOnCommitFest,
+    Tag,
     TargetVersion,
     Topic,
 )
@@ -38,8 +41,26 @@ class MailThreadAttachmentAdmin(admin.ModelAdmin):
     )
 
 
+class ColorInput(widgets.Input):
+    """
+    A color picker widget.
+    TODO: this will be natively available in Django 5.2.
+    """
+
+    input_type = "color"
+
+
+class TagAdmin(admin.ModelAdmin):
+    # Customize the Tag form with a color picker and soft validation.
+    change_form_template = "change_tag_form.html"
+    formfield_overrides = {
+        ColorField: {"widget": ColorInput},
+    }
+
+
 admin.site.register(Committer, CommitterAdmin)
 admin.site.register(CommitFest)
+admin.site.register(Tag, TagAdmin)
 admin.site.register(Topic)
 admin.site.register(Patch, PatchAdmin)
 admin.site.register(PatchHistory)
diff --git a/pgcommitfest/commitfest/forms.py b/pgcommitfest/commitfest/forms.py
index c3b9a18d..312e1d9a 100644
--- a/pgcommitfest/commitfest/forms.py
+++ b/pgcommitfest/commitfest/forms.py
@@ -5,7 +5,7 @@
 from django.http import Http404
 
 from .ajax import _archivesAPI
-from .models import MailThread, Patch, PatchOnCommitFest, TargetVersion
+from .models import MailThread, Patch, PatchOnCommitFest, Tag, TargetVersion
 from .widgets import ThreadPickWidget
 
 
@@ -13,11 +13,13 @@ class CommitFestFilterForm(forms.Form):
     selectize_fields = {
         "author": "/lookups/user",
         "reviewer": "/lookups/user",
+        "tag": None,
     }
 
     text = forms.CharField(max_length=50, required=False)
     status = forms.ChoiceField(required=False)
     targetversion = forms.ChoiceField(required=False)
+    tag = forms.ChoiceField(required=False, label="Tag (type to search)")
     author = forms.ChoiceField(required=False, label="Author (type to search)")
     reviewer = forms.ChoiceField(required=False, label="Reviewer (type to search)")
     sortkey = forms.IntegerField(required=False)
@@ -59,6 +61,9 @@ def __init__(self, data, *args, **kwargs):
         )
         self.fields["author"].choices = userchoices
         self.fields["reviewer"].choices = userchoices
+        self.fields["tag"].choices = [(-1, "* All"), (-2, "* None")] + list(
+            Tag.objects.all().values_list("id", "name")
+        )
 
         for f in (
             "status",
@@ -72,6 +77,7 @@ class PatchForm(forms.ModelForm):
     selectize_fields = {
         "authors": "/lookups/user",
         "reviewers": "/lookups/user",
+        "tags": None,
     }
 
     class Meta:
@@ -94,8 +100,14 @@ def __init__(self, *args, **kwargs):
             x.user.username,
         )
 
+        self.fields["authors"].widget.attrs["class"] = "add-user-picker"
+        self.fields["reviewers"].widget.attrs["class"] = "add-user-picker"
+
         # Selectize multiple fields -- don't pre-populate everything
         for field, url in list(self.selectize_fields.items()):
+            if url is None:
+                continue
+
             # If this is a postback of a selectize field, it may contain ids that are not currently
             # stored in the field. They must still be among the *allowed* values of course, which
             # are handled by the existing queryset on the field.
diff --git a/pgcommitfest/commitfest/migrations/0011_tag_patch_tags.py b/pgcommitfest/commitfest/migrations/0011_tag_patch_tags.py
new file mode 100644
index 00000000..6bbbaba1
--- /dev/null
+++ b/pgcommitfest/commitfest/migrations/0011_tag_patch_tags.py
@@ -0,0 +1,40 @@
+# Generated by Django 4.2.19 on 2025-05-30 18:09
+
+from django.db import migrations, models
+
+import pgcommitfest.commitfest.models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("commitfest", "0010_add_failing_since_column"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Tag",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("name", models.CharField(max_length=50, unique=True)),
+                ("color", pgcommitfest.commitfest.models.ColorField(max_length=7)),
+            ],
+            options={
+                "ordering": ("name",),
+            },
+        ),
+        migrations.AddField(
+            model_name="patch",
+            name="tags",
+            field=models.ManyToManyField(
+                blank=True, related_name="patches", to="commitfest.tag"
+            ),
+        ),
+    ]
diff --git a/pgcommitfest/commitfest/models.py b/pgcommitfest/commitfest/models.py
index fcd9edb9..f795f16a 100644
--- a/pgcommitfest/commitfest/models.py
+++ b/pgcommitfest/commitfest/models.py
@@ -102,11 +102,37 @@ def __str__(self):
         return self.version
 
 
+class ColorField(models.CharField):
+    """
+    A small wrapper around a CharField that can hold a #RRGGBB color code. The
+    primary reason to have this wrapper class is so that the TagAdmin class can
+    explicitly key off of it to inject a color picker in the admin interface.
+    """
+
+    def __init__(self, *args, **kwargs):
+        kwargs["max_length"] = 7  # for `#RRGGBB` format
+        super().__init__(*args, **kwargs)
+
+
+class Tag(models.Model):
+    """Represents a tag/label on a patch."""
+
+    name = models.CharField(max_length=50, unique=True)
+    color = ColorField()
+
+    class Meta:
+        ordering = ("name",)
+
+    def __str__(self):
+        return self.name
+
+
 class Patch(models.Model, DiffableModel):
     name = models.CharField(
         max_length=500, blank=False, null=False, verbose_name="Description"
     )
     topic = models.ForeignKey(Topic, blank=False, null=False, on_delete=models.CASCADE)
+    tags = models.ManyToManyField(Tag, related_name="patches", blank=True)
 
     # One patch can be in multiple commitfests, if it has history
     commitfests = models.ManyToManyField(CommitFest, through="PatchOnCommitFest")
diff --git a/pgcommitfest/commitfest/templates/base_form.html b/pgcommitfest/commitfest/templates/base_form.html
index 40518ca9..788627a9 100644
--- a/pgcommitfest/commitfest/templates/base_form.html
+++ b/pgcommitfest/commitfest/templates/base_form.html
@@ -75,7 +75,7 @@ <h3>Search user</h3>
  {%include "selectize_js.html" %}
  <script>
   {%if user.is_staff%}
-   $('.selectize-control').after(
+   $('.selectize-control.add-user-picker').after(
     $('<a href="#" class="btn btn-default btn-sm">Import user not listed</a>').click(function () {
      search_and_store_user();
     })
diff --git a/pgcommitfest/commitfest/templates/change_tag_form.html b/pgcommitfest/commitfest/templates/change_tag_form.html
new file mode 100644
index 00000000..124aa257
--- /dev/null
+++ b/pgcommitfest/commitfest/templates/change_tag_form.html
@@ -0,0 +1,7 @@
+{% extends 'admin/change_form.html' %}
+{% load static %}
+
+{% block admin_change_form_document_ready %}
+ {{ block.super }}
+ <script src="{% static 'commitfest/js/change_tag.js' %}" async></script>
+{% endblock %}
diff --git a/pgcommitfest/commitfest/templates/commitfest.html b/pgcommitfest/commitfest/templates/commitfest.html
index 972e0bf8..234df1a6 100644
--- a/pgcommitfest/commitfest/templates/commitfest.html
+++ b/pgcommitfest/commitfest/templates/commitfest.html
@@ -34,6 +34,7 @@ <h3>{{p.is_open|yesno:"Active patches,Closed patches"}}</h3>
       <th><a href="#" style="color:#333333;" onclick="return sortpatches(5);">Patch</a>{%if sortkey == 5%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-down"></i></div>{%elif sortkey == -5%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-up"></i></div>{%endif%}</th>
       <th><a href="#" style="color:#333333;" onclick="return sortpatches(4);">ID</a>{%if sortkey == 4%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-down"></i></div>{%elif sortkey == -4%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-up"></i></div>{%endif%}</th>
       <th>Status</th>
+      <th>Tags</th>
       <th>Ver</th>
       <th><a href="#" style="color:#333333;" onclick="return sortpatches(7);">CI status</a>{%if sortkey == 7%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-down"></i></div>{%elif sortkey == -7%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-up"></i></div>{%endif%}</th>
       <th><a href="#" style="color:#333333;" onclick="return sortpatches(6);">Stats</a>{%if sortkey == 6%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-down"></i></div>{%elif sortkey == -6%}<div style="float:right;"><i class="glyphicon glyphicon-arrow-up"></i></div>{%endif%}</th>
@@ -59,6 +60,14 @@ <h3>{{p.is_open|yesno:"Active patches,Closed patches"}}</h3>
    <td><a href="/patch/{{p.id}}/">{{p.name}}</a></td>
    <td>{{p.id}}</td>
    <td><span class="label label-{{p.status|patchstatuslabel}}">{{p.status|patchstatusstring}}</span></td>
+   <td style="width: min-content;">
+    {%for t in p.tag_ids%}
+
+     <a href="?tag={{t}}">
+      <span class="label" style="background: {{all_tags|tagcolor:t}};">{{all_tags|tagname:t}}</span>
+     </a>
+    {%endfor%}
+   </td>
    <td>{%if p.targetversion%}<span class="label label-default">{{p.targetversion}}</span>{%endif%}</td>
    <td class="cfbot-summary">
     {%with p.cfbot_results as cfb%}
diff --git a/pgcommitfest/commitfest/templates/patch.html b/pgcommitfest/commitfest/templates/patch.html
index 2aafd141..f29f6089 100644
--- a/pgcommitfest/commitfest/templates/patch.html
+++ b/pgcommitfest/commitfest/templates/patch.html
@@ -67,6 +67,14 @@
     <th>Topic</th>
     <td>{{patch.topic}}</td>
    </tr>
+   <tr>
+    <th>Tags</th>
+    <td>
+     {%for tag in patch.tags.all%}
+      <span class="label" style="background: {{tag|tagcolor}};">{{tag.name}}</span>
+     {%endfor%}
+    </td>
+   </tr>
    <tr>
     <th>Created</th>
     <td>{{patch.created}}</td>
diff --git a/pgcommitfest/commitfest/templates/selectize_js.html b/pgcommitfest/commitfest/templates/selectize_js.html
index 7cd5fb7d..0991ac65 100644
--- a/pgcommitfest/commitfest/templates/selectize_js.html
+++ b/pgcommitfest/commitfest/templates/selectize_js.html
@@ -5,19 +5,21 @@
    valueField: 'id',
    labelField: 'value',
    searchField: 'value',
-   load: function(query, callback) {
-    if (!query.length) return callback();
-    $.ajax({
-     'url': '{{url}}',
-     'type': 'GET',
-     'dataType': 'json',
-     'data': {
-      'query': query,
-     },
-     'error': function() { callback();},
-     'success': function(res) { callback(res.values);},
-    });
-   },
+   {%if url%}
+    load: function(query, callback) {
+     if (!query.length) return callback();
+     $.ajax({
+      'url': '{{url}}',
+      'type': 'GET',
+      'dataType': 'json',
+      'data': {
+       'query': query,
+      },
+      'error': function() { callback();},
+      'success': function(res) { callback(res.values);},
+     });
+    },
+   {%endif%}
    onFocus: function() {
     if (this.$input.is('[multiple]')) {
      return;
diff --git a/pgcommitfest/commitfest/templatetags/commitfest.py b/pgcommitfest/commitfest/templatetags/commitfest.py
index 25fd21f2..403d1ceb 100644
--- a/pgcommitfest/commitfest/templatetags/commitfest.py
+++ b/pgcommitfest/commitfest/templatetags/commitfest.py
@@ -6,6 +6,7 @@
 from django.utils.translation import ngettext_lazy
 
 import datetime
+import string
 from uuid import uuid4
 
 from pgcommitfest.commitfest.models import CommitFest, PatchOnCommitFest
@@ -41,6 +42,45 @@ def patchstatuslabel(value):
     return [v for k, v in PatchOnCommitFest._STATUS_LABELS if k == i][0]
 
 
+@register.filter(name="tagname")
+def tagname(value, arg):
+    """
+    Looks up a tag by ID and returns its name. The filter value is the map of
+    tags, and the argument is the ID. (Unlike tagcolor, there is no
+    argument-less variant; just use tag.name directly.)
+
+    Example:
+      tag_map|tagname:tag_id
+    """
+    return value[arg].name
+
+
+@register.filter(name="tagcolor")
+def tagcolor(value, key=None):
+    """
+    Returns the color code of a tag. The filter value is either a single tag, in
+    which case no argument should be given, or a map of tags with the tag ID as
+    the argument, as with the tagname filter.
+
+    Since color codes are injected into CSS, any nonconforming inputs are
+    replaced with black here. (Prefer `tag|tagcolor` over `tag.color` in
+    templates, for this reason.)
+    """
+    if key is not None:
+        code = value[key].color
+    else:
+        code = value.color
+
+    if (
+        len(code) == 7
+        and code.startswith("#")
+        and all(c in string.hexdigits for c in code[1:])
+    ):
+        return code
+
+    return "#000000"
+
+
 @register.filter(is_safe=True)
 def label_class(value, arg):
     return value.label_tag(attrs={"class": arg})
diff --git a/pgcommitfest/commitfest/views.py b/pgcommitfest/commitfest/views.py
index 7b6dd63d..46d6da94 100644
--- a/pgcommitfest/commitfest/views.py
+++ b/pgcommitfest/commitfest/views.py
@@ -42,6 +42,7 @@
     Patch,
     PatchHistory,
     PatchOnCommitFest,
+    Tag,
 )
 
 
@@ -262,6 +263,21 @@ def patchlist(request, cf, personalized=False):
                 # int() failed, ignore
                 pass
 
+    if request.GET.get("tag", "-1") != "-1":
+        if request.GET["tag"] == "-2":
+            whereclauses.append(
+                "NOT EXISTS (SELECT 1 FROM commitfest_patch_tags tags WHERE tags.patch_id=p.id)"
+            )
+        else:
+            try:
+                whereparams["tag"] = int(request.GET["tag"])
+                whereclauses.append(
+                    "EXISTS (SELECT 1 FROM commitfest_patch_tags tags WHERE tags.patch_id=p.id AND tags.tag_id=%(tag)s)"
+                )
+            except ValueError:
+                # int() failed -- so just ignore this filter
+                pass
+
     if request.GET.get("author", "-1") != "-1":
         if request.GET["author"] == "-2":
             whereclauses.append(
@@ -485,6 +501,7 @@ def patchlist(request, cf, personalized=False):
 (SELECT string_agg(first_name || ' ' || last_name || ' (' || username || ')', ', ') FROM auth_user INNER JOIN commitfest_patch_authors cpa ON cpa.user_id=auth_user.id WHERE cpa.patch_id=p.id) AS author_names,
 (SELECT string_agg(first_name || ' ' || last_name || ' (' || username || ')', ', ') FROM auth_user INNER JOIN commitfest_patch_reviewers cpr ON cpr.user_id=auth_user.id WHERE cpr.patch_id=p.id) AS reviewer_names,
 (SELECT count(1) FROM commitfest_patchoncommitfest pcf WHERE pcf.patch_id=p.id) AS num_cfs,
+(SELECT array_agg(tag_id) FROM commitfest_patch_tags t WHERE t.patch_id=p.id) AS tag_ids,
 
 branch.needs_rebase_since,
 branch.failing_since,
@@ -531,6 +548,7 @@ def patchlist(request, cf, personalized=False):
     )
 
 
+@transaction.atomic  # tie the patchlist() query to Tag.objects.all()
 def commitfest(request, cfid):
     # Find ourselves
     cf = get_object_or_404(CommitFest, pk=cfid)
@@ -562,6 +580,7 @@ def commitfest(request, cfid):
             "form": form,
             "patches": patch_list.patches,
             "statussummary": statussummary,
+            "all_tags": {t.id: t for t in Tag.objects.all()},
             "has_filter": patch_list.has_filter,
             "title": cf.title,
             "grouping": patch_list.sortkey == 0,