See the Default Schema of SQL Server Database Users and Groups

To see the default schema of database users, use the following query:

SELECT name, type_desc, default_schema_name
FROM sys.database_principals
WHERE type in ('S', 'U');

default_schema_database_users

SQL Server 2012 introduced the default schema for Windows groups. You can use the following query, that lists default schema of database users and groups:

SELECT name, type_desc, default_schema_name
FROM sys.database_principals
WHERE type in ('S', 'U', 'G');

default_schema_database_users_groups