diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9eb34bc..ec30bdc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.14.0]
+- Added: new param `defaultTenant` to the `hasSourceTenantsForMetrics` validator to set the default tenant for the rule group.
+
 ## [2.13.0] - 2024-03-08
 - Added: support for disabling validation using comments in yaml rules per rule group and for the whole file.
 - Docs: Updated/improved documentation on how to disable validations and validation rules.
diff --git a/docs/validations.md b/docs/validations.md
index c946043..34cc2e2 100644
--- a/docs/validations.md
+++ b/docs/validations.md
@@ -317,6 +317,7 @@ Fails, if the rule uses metric, that matches the specified regular expression fo
 
 ```yaml
 params:
+  defaultTenant: <tenant_name> # Optional, if set, the tenant that will be assumed if the group does not have the `source_tenants` option set
   sourceTenants:
     <tenant_name>:
       - regexp: <metric_name_regexp> # The regexp will be fully anchored (surrounded by ^...$)
diff --git a/pkg/validator/others.go b/pkg/validator/others.go
index 2380b36..313a151 100644
--- a/pkg/validator/others.go
+++ b/pkg/validator/others.go
@@ -20,6 +20,7 @@ type SourceTenantMetrics struct {
 func newHasSourceTenantsForMetrics(paramsConfig yaml.Node) (Validator, error) {
 	params := struct {
 		SourceTenants map[string][]SourceTenantMetrics `yaml:"sourceTenants"`
+		DefaultTenant string                           `yaml:"defaultTenant"`
 	}{}
 	if err := paramsConfig.Decode(&params); err != nil {
 		return nil, err
@@ -27,7 +28,7 @@ func newHasSourceTenantsForMetrics(paramsConfig yaml.Node) (Validator, error) {
 	if params.SourceTenants == nil || len(params.SourceTenants) == 0 {
 		return nil, fmt.Errorf("sourceTenants metrics mapping needs to be set")
 	}
-	validator := hasSourceTenantsForMetrics{sourceTenants: map[string][]tenantMetrics{}}
+	validator := hasSourceTenantsForMetrics{sourceTenants: map[string][]tenantMetrics{}, defaultTenant: params.DefaultTenant}
 	for tenant, metrics := range params.SourceTenants {
 		m := make([]tenantMetrics, len(metrics))
 		for i, metric := range metrics {
@@ -52,6 +53,7 @@ type tenantMetrics struct {
 
 type hasSourceTenantsForMetrics struct {
 	sourceTenants map[string][]tenantMetrics
+	defaultTenant string
 }
 
 func (h hasSourceTenantsForMetrics) String() string {
@@ -79,7 +81,13 @@ func (h hasSourceTenantsForMetrics) Validate(group unmarshaler.RuleGroup, rule r
 	for _, usedMetric := range usedMetrics {
 		for tenant, metrics := range h.sourceTenants {
 			for _, metric := range metrics {
-				if metric.regexp.MatchString(usedMetric.Name) && !slices.Contains(group.SourceTenants, tenant) {
+				if !metric.regexp.MatchString(usedMetric.Name) {
+					continue
+				}
+				if len(group.SourceTenants) == 0 && h.defaultTenant == tenant {
+					continue
+				}
+				if !slices.Contains(group.SourceTenants, tenant) {
 					errs = append(errs, fmt.Errorf("rule uses metric `%s` of the tenant `%s` tenant, you should set the tenant in the groups source_tenants settings", tenant, usedMetric.Name))
 				}
 			}
diff --git a/pkg/validator/validator_test.go b/pkg/validator/validator_test.go
index 4e5c585..9f844bd 100644
--- a/pkg/validator/validator_test.go
+++ b/pkg/validator/validator_test.go
@@ -201,6 +201,8 @@ var testCases = []struct {
 	{name: "usesMetricWithSourceTenantAndGroupDoesNotHaveSourceTenant", validator: hasSourceTenantsForMetrics{sourceTenants: map[string][]tenantMetrics{"tenant1": {{regexp: regexp.MustCompile(`^teanant1_metric$`)}}}}, group: unmarshaler.RuleGroup{SourceTenants: []string{"tenant2"}}, rule: rulefmt.Rule{Expr: `teanant1_metric{foo="bar"}`}, expectedErrors: 1},
 	{name: "usesMetricWithSourceTenantAndGroupHasMultipleSourceTenants", validator: hasSourceTenantsForMetrics{sourceTenants: map[string][]tenantMetrics{"tenant1": {{regexp: regexp.MustCompile(`^teanant1_metric$`)}}}}, group: unmarshaler.RuleGroup{SourceTenants: []string{"tenant2", "tenant1"}}, rule: rulefmt.Rule{Expr: `teanant1_metric{foo="bar"}`}, expectedErrors: 0},
 	{name: "usesMetricWithSourceTenantAndGroupHasMultipleSourceTenantsAndOneIsMissing", validator: hasSourceTenantsForMetrics{sourceTenants: map[string][]tenantMetrics{"tenant1": {{regexp: regexp.MustCompile(`^teanant1_metric$`)}}}}, group: unmarshaler.RuleGroup{SourceTenants: []string{"tenant2", "tenant3"}}, rule: rulefmt.Rule{Expr: `teanant1_metric{foo="bar"}`}, expectedErrors: 1},
+	{name: "doesNotHaveSourceTenantForMetricButIsDefault", validator: hasSourceTenantsForMetrics{defaultTenant: "tenant1", sourceTenants: map[string][]tenantMetrics{"tenant1": {{regexp: regexp.MustCompile(`^teanant1_metric$`)}}}}, group: unmarshaler.RuleGroup{SourceTenants: []string{}}, rule: rulefmt.Rule{Expr: `teanant1_metric{foo="bar"}`}, expectedErrors: 0},
+	{name: "doesNotHaveSourceTenantForMetricAndIsNotDefault", validator: hasSourceTenantsForMetrics{defaultTenant: "tenant2", sourceTenants: map[string][]tenantMetrics{"tenant1": {{regexp: regexp.MustCompile(`^teanant1_metric$`)}}}}, group: unmarshaler.RuleGroup{SourceTenants: []string{}}, rule: rulefmt.Rule{Expr: `teanant1_metric{foo="bar"}`}, expectedErrors: 1},
 
 	// hasAllowedSourceTenants
 	{name: "emptyAllowedSourceTenantsAndGroupSourceTenants", validator: hasAllowedSourceTenants{allowedSourceTenants: []string{}}, group: unmarshaler.RuleGroup{SourceTenants: []string{}}, rule: rulefmt.Rule{Expr: `up{foo="bar"}`}, expectedErrors: 0},