diff --git a/models/unit/unit.go b/models/unit/unit.go
index b216712d3..e37adf995 100644
--- a/models/unit/unit.go
+++ b/models/unit/unit.go
@@ -108,6 +108,10 @@ var (
 
 	// DisabledRepoUnits contains the units that have been globally disabled
 	DisabledRepoUnits = []Type{}
+
+	// AllowedRepoUnitGroups contains the units that have been globally enabled,
+	// with mutually exclusive units grouped together.
+	AllowedRepoUnitGroups = [][]Type{}
 )
 
 // Get valid set of default repository units from settings
@@ -162,6 +166,45 @@ func LoadUnitConfig() error {
 	if len(DefaultForkRepoUnits) == 0 {
 		return errors.New("no default fork repository units found")
 	}
+
+	// Collect the allowed repo unit groups. Mutually exclusive units are
+	// grouped together.
+	AllowedRepoUnitGroups = [][]Type{}
+	for _, unit := range []Type{
+		TypeCode,
+		TypePullRequests,
+		TypeProjects,
+		TypePackages,
+		TypeActions,
+	} {
+		// If unit is globally disabled, ignore it.
+		if unit.UnitGlobalDisabled() {
+			continue
+		}
+
+		// If it is allowed, add it to the group list.
+		AllowedRepoUnitGroups = append(AllowedRepoUnitGroups, []Type{unit})
+	}
+
+	addMutuallyExclusiveGroup := func(unit1, unit2 Type) {
+		var list []Type
+
+		if !unit1.UnitGlobalDisabled() {
+			list = append(list, unit1)
+		}
+
+		if !unit2.UnitGlobalDisabled() {
+			list = append(list, unit2)
+		}
+
+		if len(list) > 0 {
+			AllowedRepoUnitGroups = append(AllowedRepoUnitGroups, list)
+		}
+	}
+
+	addMutuallyExclusiveGroup(TypeIssues, TypeExternalTracker)
+	addMutuallyExclusiveGroup(TypeWiki, TypeExternalWiki)
+
 	return nil
 }
 
diff --git a/modules/context/repo.go b/modules/context/repo.go
index b48f6ded2..727c18cad 100644
--- a/modules/context/repo.go
+++ b/modules/context/repo.go
@@ -81,6 +81,31 @@ func (r *Repository) CanCreateBranch() bool {
 	return r.Permission.CanWrite(unit_model.TypeCode) && r.Repository.CanCreateBranch()
 }
 
+// AllUnitsEnabled returns true if all units are enabled for the repo.
+func (r *Repository) AllUnitsEnabled(ctx context.Context) bool {
+	hasAnyUnitEnabled := func(unitGroup []unit_model.Type) bool {
+		// Loop over the group of units
+		for _, unit := range unitGroup {
+			// If *any* of them is enabled, return true.
+			if r.Repository.UnitEnabled(ctx, unit) {
+				return true
+			}
+		}
+
+		// If none are enabled, return false.
+		return false
+	}
+
+	for _, unitGroup := range unit_model.AllowedRepoUnitGroups {
+		// If any disabled unit is found, return false immediately.
+		if !hasAnyUnitEnabled(unitGroup) {
+			return false
+		}
+	}
+
+	return true
+}
+
 // RepoMustNotBeArchived checks if a repo is archived
 func RepoMustNotBeArchived() func(ctx *Context) {
 	return func(ctx *Context) {
@@ -1053,6 +1078,7 @@ func RepoRefByType(refType RepoRefType, ignoreNotExistErr ...bool) func(*Context
 		ctx.Data["IsViewTag"] = ctx.Repo.IsViewTag
 		ctx.Data["IsViewCommit"] = ctx.Repo.IsViewCommit
 		ctx.Data["CanCreateBranch"] = ctx.Repo.CanCreateBranch()
+		ctx.Data["AllUnitsEnabled"] = ctx.Repo.AllUnitsEnabled(ctx)
 
 		ctx.Repo.CommitsCount, err = ctx.Repo.GetCommitsCount()
 		if err != nil {
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index be2a06b38..9c8b3fc54 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -2068,6 +2068,7 @@ settings.mirror_settings.push_mirror.edit_sync_time = Edit mirror sync interval
 
 settings.units.units = Repository Units
 settings.units.overview = Overview
+settings.units.add_more = Add more...
 
 settings.sync_mirror = Synchronize Now
 settings.pull_mirror_sync_in_progress = Pulling changes from the remote %s at the moment.
diff --git a/templates/repo/header.tmpl b/templates/repo/header.tmpl
index ef3e40eea..681cba9ef 100644
--- a/templates/repo/header.tmpl
+++ b/templates/repo/header.tmpl
@@ -219,6 +219,11 @@
 				{{end}}
 
 				{{if .Permission.IsAdmin}}
+					{{if not .AllUnitsEnabled}}
+						<a class="{{if .PageIsRepoSettingsUnits}}active {{end}}item" href="{{.RepoLink}}/settings/units">
+							{{svg "octicon-diff-added"}} {{ctx.Locale.Tr "repo.settings.units.add_more"}}
+						</a>
+					{{end}}
 					<a class="{{if .PageIsRepoSettings}}active {{end}} item" href="{{.RepoLink}}/settings">
 						{{svg "octicon-tools"}} {{ctx.Locale.Tr "repo.settings"}}
 					</a>