diff --git a/CHANGELOG.md b/CHANGELOG.md
index be2d36c77..870d74f7b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file. From versio
 
 ## Unreleased
 
+### Fixed
+
+- Fix login with uppercase and mixed case role names by @taimoorzaeem in #4678
+
 ## [14.10] - 2026-04-16
 
 ### Added
diff --git a/nix/tools/withTools.nix b/nix/tools/withTools.nix
index 2f6afe4c4..4ec6109bf 100644
--- a/nix/tools/withTools.nix
+++ b/nix/tools/withTools.nix
@@ -25,7 +25,7 @@ let
             "ARG_OPTIONAL_SINGLE([fixtures], [f], [SQL file to load fixtures from])"
             "ARG_POSITIONAL_SINGLE([command], [Command to run])"
             "ARG_LEFTOVERS([command arguments])"
-            "ARG_USE_ENV([PGUSER], [postgrest_test_authenticator], [Authenticator PG role])"
+            "ARG_USE_ENV([PGUSER], [Postgrest_Test_Authenticator], [Authenticator PG role])" # user is written in mixed case to implicitly test that it is being properly quoted in schema cache queries
             "ARG_USE_ENV([PGDATABASE], [postgres], [PG database name])"
             "ARG_USE_ENV([PGRST_DB_SCHEMAS], [test], [Schema to expose])"
             "ARG_USE_ENV([PGTZ], [utc], [Timezone to use])"
diff --git a/src/PostgREST/Config/Database.hs b/src/PostgREST/Config/Database.hs
index aff4b5b8a..8b8661098 100644
--- a/src/PostgREST/Config/Database.hs
+++ b/src/PostgREST/Config/Database.hs
@@ -101,7 +101,7 @@ queryDbSettings preConfFunc prepared =
         SELECT setdatabase as database,
                unnest(setconfig) as setting
         FROM pg_catalog.pg_db_role_setting
-        WHERE setrole = CURRENT_USER::regrole::oid
+        WHERE setrole = quote_ident(CURRENT_USER)::regrole::oid
           AND setdatabase IN (0, (SELECT oid FROM pg_catalog.pg_database WHERE datname = CURRENT_CATALOG))
       ),
       kv_settings AS (
@@ -142,7 +142,7 @@ queryRoleSettings pgVer prepared =
         select r.rolname, unnest(r.rolconfig) as setting
         from pg_auth_members m
         join pg_roles r on r.oid = m.roleid
-        where member = current_user::regrole::oid
+        where member = quote_ident(current_user)::regrole::oid
       ),
       kv_settings AS (
         SELECT
@@ -167,7 +167,7 @@ queryRoleSettings pgVer prepared =
     |]
 
     hasParameterPrivilege
-      | pgVer >= pgVersion150 = "or has_parameter_privilege(current_user::regrole::oid, ps.name, 'set')"
+      | pgVer >= pgVersion150 = "or has_parameter_privilege(quote_ident(current_user)::regrole::oid, ps.name, 'set')"
       | otherwise             = ""
 
     processRows :: [(Text, Maybe Text, [(Text, Text)])] -> (RoleSettings, RoleIsolationLvl)
diff --git a/test/io/fixtures/big_schema.sql b/test/io/fixtures/big_schema.sql
index 6984164a6..559b434df 100644
--- a/test/io/fixtures/big_schema.sql
+++ b/test/io/fixtures/big_schema.sql
@@ -11399,7 +11399,7 @@ $$;
 DROP ROLE IF EXISTS postgrest_test_anonymous;
 CREATE ROLE postgrest_test_anonymous;
 
-GRANT postgrest_test_anonymous TO :PGUSER;
+GRANT postgrest_test_anonymous TO :"PGUSER";
 
 GRANT USAGE ON SCHEMA apflora TO postgrest_test_anonymous;
 GRANT USAGE ON SCHEMA fuzzysearch TO postgrest_test_anonymous;
diff --git a/test/io/fixtures/load.sql b/test/io/fixtures/load.sql
index cbb70f6a1..bda30ac91 100644
--- a/test/io/fixtures/load.sql
+++ b/test/io/fixtures/load.sql
@@ -4,7 +4,7 @@ set check_function_bodies = false; -- to allow conditionals based on the pg vers
 set search_path to public;
 
 CREATE ROLE postgrest_test_anonymous;
-ALTER ROLE :PGUSER SET pgrst.db_anon_role = 'postgrest_test_anonymous';
+ALTER ROLE :"PGUSER" SET pgrst.db_anon_role = 'postgrest_test_anonymous';
 
 CREATE ROLE postgrest_test_author;
 
@@ -21,14 +21,14 @@ alter role postgrest_test_w_superuser_settings set log_min_messages = 'fatal';
 DO $do$BEGIN
   IF (SELECT current_setting('server_version_num')::INT >= 150000) THEN
     ALTER ROLE postgrest_test_w_superuser_settings SET log_min_duration_sample = 12345;
-    GRANT SET ON PARAMETER log_min_duration_sample to postgrest_test_authenticator;
+    GRANT SET ON PARAMETER log_min_duration_sample to "Postgrest_Test_Authenticator";
   END IF;
 END$do$;
 
 GRANT
   postgrest_test_anonymous, postgrest_test_author,
   postgrest_test_serializable, postgrest_test_repeatable_read,
-  postgrest_test_w_superuser_settings TO :PGUSER;
+  postgrest_test_w_superuser_settings TO :"PGUSER";
 
 CREATE SCHEMA v1;
 GRANT USAGE ON SCHEMA v1 TO postgrest_test_anonymous;
@@ -57,7 +57,7 @@ $$ language sql;
 create function change_max_rows_config(val int, notify bool default false) returns void as $_$
 begin
   execute format($$
-    alter role postgrest_test_authenticator set pgrst.db_max_rows = %L;
+    alter role "Postgrest_Test_Authenticator" set pgrst.db_max_rows = %L;
   $$, val);
   if notify then
     perform pg_notify('pgrst', 'reload config');
@@ -66,13 +66,13 @@ end $_$ volatile security definer language plpgsql ;
 
 create function reset_max_rows_config() returns void as $_$
 begin
-  alter role postgrest_test_authenticator reset pgrst.db_max_rows;
+  alter role "Postgrest_Test_Authenticator" reset pgrst.db_max_rows;
 end $_$ volatile security definer language plpgsql ;
 
 create function change_db_schema_and_full_reload(schemas text) returns void as $_$
 begin
   execute format($$
-    alter role postgrest_test_authenticator set pgrst.db_schemas = %L;
+    alter role "Postgrest_Test_Authenticator" set pgrst.db_schemas = %L;
   $$, schemas);
   perform pg_notify('pgrst', 'reload config');
   perform pg_notify('pgrst', 'reload schema');
@@ -80,14 +80,14 @@ end $_$ volatile security definer language plpgsql ;
 
 create function v1.reset_db_schema_config() returns void as $_$
 begin
-  alter role postgrest_test_authenticator reset pgrst.db_schemas;
+  alter role "Postgrest_Test_Authenticator" reset pgrst.db_schemas;
   perform pg_notify('pgrst', 'reload config');
   perform pg_notify('pgrst', 'reload schema');
 end $_$ volatile security definer language plpgsql ;
 
 create function invalid_role_claim_key_reload() returns void as $_$
 begin
-  alter role postgrest_test_authenticator set pgrst.jwt_role_claim_key = 'test';
+  alter role "Postgrest_Test_Authenticator" set pgrst.jwt_role_claim_key = 'test';
   perform pg_notify('pgrst', 'reload config');
 end $_$ volatile security definer language plpgsql ;
 
@@ -100,7 +100,7 @@ $_$ language sql;
 
 create function reset_invalid_role_claim_key() returns void as $_$
 begin
-  alter role postgrest_test_authenticator reset pgrst.jwt_role_claim_key;
+  alter role "Postgrest_Test_Authenticator" reset pgrst.jwt_role_claim_key;
   perform pg_notify('pgrst', 'reload config');
 end $_$ volatile security definer language plpgsql ;
 
@@ -235,12 +235,12 @@ $$ language sql;
 
 create function change_db_schemas_config() returns void as $_$
 begin
-  alter role postgrest_test_authenticator set pgrst.db_schemas = 'test';
+  alter role "Postgrest_Test_Authenticator" set pgrst.db_schemas = 'test';
 end $_$ volatile security definer language plpgsql;
 
 create function reset_db_schemas_config() returns void as $_$
 begin
-  alter role postgrest_test_authenticator reset pgrst.db_schemas;
+  alter role "Postgrest_Test_Authenticator" reset pgrst.db_schemas;
 end $_$ volatile security definer language plpgsql ;
 
 create function test.get_current_schema() returns text as $$
diff --git a/test/io/fixtures/replica.sql b/test/io/fixtures/replica.sql
index deffbec06..bf765fdb3 100644
--- a/test/io/fixtures/replica.sql
+++ b/test/io/fixtures/replica.sql
@@ -13,7 +13,7 @@ create table replica.items as select x as id from generate_series(1, 10) x;
 DROP ROLE IF EXISTS postgrest_test_anonymous;
 CREATE ROLE postgrest_test_anonymous;
 
-GRANT postgrest_test_anonymous TO :PGUSER;
+GRANT postgrest_test_anonymous TO :"PGUSER";
 
 GRANT USAGE ON SCHEMA replica TO postgrest_test_anonymous;
 
diff --git a/test/load/fixtures.sql b/test/load/fixtures.sql
index 3622dcf78..75bd6a8bb 100644
--- a/test/load/fixtures.sql
+++ b/test/load/fixtures.sql
@@ -1,7 +1,7 @@
 CREATE ROLE postgrest_test_anonymous;
 CREATE ROLE postgrest_test_author;
-GRANT postgrest_test_anonymous TO :PGUSER;
-GRANT postgrest_test_author TO :PGUSER;
+GRANT postgrest_test_anonymous TO :"PGUSER";
+GRANT postgrest_test_author TO :"PGUSER";
 CREATE SCHEMA test;
 
 -- PUT+PATCH target needs one record and column to modify
diff --git a/test/observability/fixtures/roles.sql b/test/observability/fixtures/roles.sql
index e0a938b60..ef6f444ee 100644
--- a/test/observability/fixtures/roles.sql
+++ b/test/observability/fixtures/roles.sql
@@ -2,4 +2,4 @@ DROP ROLE IF EXISTS postgrest_test_anonymous, postgrest_test_author;
 CREATE ROLE postgrest_test_anonymous;
 CREATE ROLE postgrest_test_author;
 
-GRANT postgrest_test_anonymous, postgrest_test_author TO :PGUSER;
+GRANT postgrest_test_anonymous, postgrest_test_author TO :"PGUSER";
diff --git a/test/spec/fixtures/roles.sql b/test/spec/fixtures/roles.sql
index 3590c6edb..f1b7e1ca7 100644
--- a/test/spec/fixtures/roles.sql
+++ b/test/spec/fixtures/roles.sql
@@ -4,4 +4,4 @@ CREATE ROLE postgrest_test_default_role;
 CREATE ROLE postgrest_test_author;
 CREATE ROLE postgrest_test_superuser WITH SUPERUSER;
 
-GRANT postgrest_test_anonymous, postgrest_test_default_role, postgrest_test_author, postgrest_test_superuser TO :PGUSER;
+GRANT postgrest_test_anonymous, postgrest_test_default_role, postgrest_test_author, postgrest_test_superuser TO :"PGUSER";