diff --git a/internal/sdkprovider/service/account/account_team_member.go b/internal/sdkprovider/service/account/account_team_member.go
index 0b7a010e5..1891bfed1 100644
--- a/internal/sdkprovider/service/account/account_team_member.go
+++ b/internal/sdkprovider/service/account/account_team_member.go
@@ -3,6 +3,7 @@ package account
 import (
 	"context"
 	"log"
+	"strings"
 
 	"github.com/aiven/aiven-go-client/v2"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
@@ -76,7 +77,7 @@ func resourceAccountTeamMemberCreate(ctx context.Context, d *schema.ResourceData
 	client := m.(*aiven.Client)
 	accountID := d.Get("account_id").(string)
 	teamID := d.Get("team_id").(string)
-	userEmail := d.Get("user_email").(string)
+	userEmail := strings.ToLower(d.Get("user_email").(string))
 
 	err := client.AccountTeamMembers.Invite(
 		ctx,
diff --git a/internal/sdkprovider/service/account/account_team_member_data_source.go b/internal/sdkprovider/service/account/account_team_member_data_source.go
index a4c0b770a..536d3e2c1 100644
--- a/internal/sdkprovider/service/account/account_team_member_data_source.go
+++ b/internal/sdkprovider/service/account/account_team_member_data_source.go
@@ -2,6 +2,7 @@ package account
 
 import (
 	"context"
+	"strings"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
@@ -21,7 +22,7 @@ func DatasourceAccountTeamMember() *schema.Resource {
 func datasourceAccountTeamMemberRead(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
 	accountID := d.Get("account_id").(string)
 	teamID := d.Get("team_id").(string)
-	userEmail := d.Get("user_email").(string)
+	userEmail := strings.ToLower(d.Get("user_email").(string))
 
 	d.SetId(schemautil.BuildResourceID(accountID, teamID, userEmail))
 
diff --git a/internal/sdkprovider/service/organization/organization_user.go b/internal/sdkprovider/service/organization/organization_user.go
index 60e75f62f..22e89a1d6 100644
--- a/internal/sdkprovider/service/organization/organization_user.go
+++ b/internal/sdkprovider/service/organization/organization_user.go
@@ -3,6 +3,7 @@ package organization
 import (
 	"context"
 	"log"
+	"strings"
 
 	"github.com/aiven/aiven-go-client/v2"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
@@ -70,7 +71,7 @@ eliminate the member from the organization if one has accepted an invitation pre
 func resourceOrganizationUserCreate(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
 	client := m.(*aiven.Client)
 	organizationID := d.Get("organization_id").(string)
-	userEmail := d.Get("user_email").(string)
+	userEmail := strings.ToLower(d.Get("user_email").(string))
 
 	err := client.OrganizationUserInvitations.Invite(ctx, organizationID, aiven.OrganizationUserInvitationAddRequest{
 		UserEmail: userEmail,
diff --git a/internal/sdkprovider/service/organization/organization_user_data_source.go b/internal/sdkprovider/service/organization/organization_user_data_source.go
index 85c341ab8..f760bb64c 100644
--- a/internal/sdkprovider/service/organization/organization_user_data_source.go
+++ b/internal/sdkprovider/service/organization/organization_user_data_source.go
@@ -2,6 +2,7 @@ package organization
 
 import (
 	"context"
+	"strings"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
@@ -22,7 +23,7 @@ func DatasourceOrganizationUser() *schema.Resource {
 
 func datasourceOrganizationUserRead(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
 	organizationID := d.Get("organization_id").(string)
-	userEmail := d.Get("user_email").(string)
+	userEmail := strings.ToLower(d.Get("user_email").(string))
 
 	d.SetId(schemautil.BuildResourceID(organizationID, userEmail))
 
diff --git a/internal/sdkprovider/service/project/project_user.go b/internal/sdkprovider/service/project/project_user.go
index 7480f0bb3..0dc6deaf6 100644
--- a/internal/sdkprovider/service/project/project_user.go
+++ b/internal/sdkprovider/service/project/project_user.go
@@ -62,7 +62,7 @@ func isProjectUserAlreadyInvited(err error) bool {
 func resourceProjectUserCreate(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
 	client := m.(*aiven.Client)
 	projectName := d.Get("project").(string)
-	email := d.Get("email").(string)
+	email := strings.ToLower(d.Get("email").(string))
 	err := client.ProjectUsers.Invite(
 		ctx,
 		projectName,
diff --git a/internal/sdkprovider/service/project/project_user_data_source.go b/internal/sdkprovider/service/project/project_user_data_source.go
index 3e2228dbe..6146c08bb 100644
--- a/internal/sdkprovider/service/project/project_user_data_source.go
+++ b/internal/sdkprovider/service/project/project_user_data_source.go
@@ -2,6 +2,7 @@ package project
 
 import (
 	"context"
+	"strings"
 
 	"github.com/aiven/aiven-go-client/v2"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
@@ -23,7 +24,7 @@ func datasourceProjectUserRead(ctx context.Context, d *schema.ResourceData, m in
 	client := m.(*aiven.Client)
 
 	projectName := d.Get("project").(string)
-	email := d.Get("email").(string)
+	email := strings.ToLower(d.Get("email").(string))
 
 	users, invitations, err := client.ProjectUsers.List(ctx, projectName)
 	if err != nil {