diff --git a/src/test_utils.rs b/src/test_utils.rs
index c1d86d6..391a44c 100644
--- a/src/test_utils.rs
+++ b/src/test_utils.rs
@@ -19,6 +19,8 @@ use testcontainers::{runners::AsyncRunner, ContainerAsync, ImageExt};
 use testcontainers_modules::postgres::Postgres;
 #[cfg(any(test, feature = "test-utils"))]
 use tower::util::ServiceExt;
+#[cfg(any(test, feature = "test-utils"))]
+use uuid;
 
 /// Test image information with expected OCR content
 #[derive(Debug, Clone)]
@@ -221,9 +223,14 @@ pub async fn create_test_app() -> (Router, ContainerAsync<Postgres>) {
 
 #[cfg(any(test, feature = "test-utils"))]
 pub async fn create_test_user(app: &Router) -> UserResponse {
+    // Generate random identifiers to avoid test interference
+    let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+    let test_username = format!("testuser_{}", test_id);
+    let test_email = format!("test_{}@example.com", test_id);
+    
     let user_data = json!({
-        "username": "testuser",
-        "email": "test@example.com",
+        "username": test_username,
+        "email": test_email,
         "password": "password123"
     });
     
@@ -248,9 +255,14 @@ pub async fn create_test_user(app: &Router) -> UserResponse {
 
 #[cfg(any(test, feature = "test-utils"))]
 pub async fn create_admin_user(app: &Router) -> UserResponse {
+    // Generate random identifiers to avoid test interference
+    let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+    let admin_username = format!("adminuser_{}", test_id);
+    let admin_email = format!("admin_{}@example.com", test_id);
+    
     let admin_data = json!({
-        "username": "adminuser",
-        "email": "admin@example.com",
+        "username": admin_username,
+        "email": admin_email,
         "password": "adminpass123",
         "role": "admin"
     });
diff --git a/src/tests/config_oidc_tests.rs b/src/tests/config_oidc_tests.rs
index d6eaff2..e5a1b5c 100644
--- a/src/tests/config_oidc_tests.rs
+++ b/src/tests/config_oidc_tests.rs
@@ -120,6 +120,15 @@ mod tests {
 
     #[test]
     fn test_oidc_partial_config() {
+        // Clean up environment first to ensure test isolation
+        env::remove_var("OIDC_ENABLED");
+        env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
+        env::remove_var("DATABASE_URL");
+        env::remove_var("JWT_SECRET");
+        
         // Only set some OIDC vars
         env::set_var("OIDC_ENABLED", "true");
         env::set_var("OIDC_CLIENT_ID", "test-client-id");
@@ -138,12 +147,24 @@ mod tests {
         // Clean up
         env::remove_var("OIDC_ENABLED");
         env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
         env::remove_var("DATABASE_URL");
         env::remove_var("JWT_SECRET");
     }
 
     #[test]
     fn test_oidc_disabled_with_config_present() {
+        // Clean up environment first to ensure test isolation
+        env::remove_var("OIDC_ENABLED");
+        env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
+        env::remove_var("DATABASE_URL");
+        env::remove_var("JWT_SECRET");
+        
         // OIDC disabled but config present
         env::set_var("OIDC_ENABLED", "false");
         env::set_var("OIDC_CLIENT_ID", "test-client-id");
@@ -173,6 +194,15 @@ mod tests {
 
     #[test]
     fn test_oidc_empty_values() {
+        // Clean up environment first to ensure test isolation
+        env::remove_var("OIDC_ENABLED");
+        env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
+        env::remove_var("DATABASE_URL");
+        env::remove_var("JWT_SECRET");
+        
         env::set_var("OIDC_ENABLED", "true");
         env::set_var("OIDC_CLIENT_ID", "");
         env::set_var("OIDC_CLIENT_SECRET", "");
@@ -202,6 +232,15 @@ mod tests {
 
     #[test]
     fn test_oidc_config_validation_output() {
+        // Clean up environment first to ensure test isolation
+        env::remove_var("OIDC_ENABLED");
+        env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
+        env::remove_var("DATABASE_URL");
+        env::remove_var("JWT_SECRET");
+        
         // Test that validation warnings are properly formatted
         env::set_var("OIDC_ENABLED", "true");
         env::set_var("DATABASE_URL", "postgresql://test:test@localhost/test");
@@ -215,12 +254,25 @@ mod tests {
 
         // Clean up
         env::remove_var("OIDC_ENABLED");
+        env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
         env::remove_var("DATABASE_URL");
         env::remove_var("JWT_SECRET");
     }
 
     #[test]
     fn test_oidc_complete_configuration() {
+        // Clean up environment first to ensure test isolation
+        env::remove_var("OIDC_ENABLED");
+        env::remove_var("OIDC_CLIENT_ID");
+        env::remove_var("OIDC_CLIENT_SECRET");
+        env::remove_var("OIDC_ISSUER_URL");
+        env::remove_var("OIDC_REDIRECT_URI");
+        env::remove_var("DATABASE_URL");
+        env::remove_var("JWT_SECRET");
+        
         env::set_var("OIDC_ENABLED", "true");
         env::set_var("OIDC_CLIENT_ID", "my-app-client-id");
         env::set_var("OIDC_CLIENT_SECRET", "super-secret-client-secret");
diff --git a/src/tests/oidc_tests.rs b/src/tests/oidc_tests.rs
index e088bfd..9d40fce 100644
--- a/src/tests/oidc_tests.rs
+++ b/src/tests/oidc_tests.rs
@@ -7,6 +7,7 @@ mod tests {
     use wiremock::{matchers::{method, path, query_param, header}, Mock, MockServer, ResponseTemplate};
     use std::sync::Arc;
     use crate::{AppState, oidc::OidcClient};
+    use uuid;
 
     async fn create_test_app_simple() -> (axum::Router, ()) {
         // Use TEST_DATABASE_URL directly, no containers
@@ -239,6 +240,12 @@ mod tests {
     async fn test_oidc_callback_success_new_user() {
         let (app, mock_server) = create_test_app_with_oidc().await;
         
+        // Generate random identifiers to avoid test interference
+        let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+        let test_username = format!("oidcuser_{}", test_id);
+        let test_email = format!("oidc_{}@example.com", test_id);
+        let test_subject = format!("oidc-user-{}", test_id);
+        
         // Clean up any existing test user to ensure test isolation
         let database_url = std::env::var("TEST_DATABASE_URL")
             .or_else(|_| std::env::var("DATABASE_URL"))
@@ -247,8 +254,8 @@ mod tests {
         
         // Delete any existing user with the test username or OIDC subject
         let _ = sqlx::query("DELETE FROM users WHERE username = $1 OR oidc_subject = $2")
-            .bind("oidcuser")
-            .bind("oidc-user-123")
+            .bind(&test_username)
+            .bind(&test_subject)
             .execute(&db.pool)
             .await;
         
@@ -271,10 +278,10 @@ mod tests {
 
         // Mock user info
         let user_info_response = json!({
-            "sub": "oidc-user-123",
-            "email": "oidc@example.com",
+            "sub": test_subject,
+            "email": test_email,
             "name": "OIDC User",
-            "preferred_username": "oidcuser"
+            "preferred_username": test_username
         });
 
         Mock::given(method("GET"))
@@ -327,8 +334,8 @@ mod tests {
         let login_response: serde_json::Value = serde_json::from_slice(&body).unwrap();
         
         assert!(login_response["token"].is_string());
-        assert_eq!(login_response["user"]["username"], "oidcuser");
-        assert_eq!(login_response["user"]["email"], "oidc@example.com");
+        assert_eq!(login_response["user"]["username"], test_username);
+        assert_eq!(login_response["user"]["email"], test_email);
     }
 
     #[tokio::test]
@@ -362,6 +369,11 @@ mod tests {
     async fn test_oidc_callback_invalid_user_info() {
         let (app, mock_server) = create_test_app_with_oidc().await;
         
+        // Generate random identifiers to avoid test interference
+        let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+        let test_username = format!("oidcuser_{}", test_id);
+        let test_subject = format!("oidc-user-{}", test_id);
+        
         // Clean up any existing test user to ensure test isolation
         let database_url = std::env::var("TEST_DATABASE_URL")
             .or_else(|_| std::env::var("DATABASE_URL"))
@@ -369,7 +381,9 @@ mod tests {
         let db = crate::db::Database::new(&database_url).await.unwrap();
         
         // Delete any existing user that might conflict
-        let _ = sqlx::query("DELETE FROM users WHERE username LIKE 'oidc%' OR oidc_subject IS NOT NULL")
+        let _ = sqlx::query("DELETE FROM users WHERE username = $1 OR oidc_subject = $2")
+            .bind(&test_username)
+            .bind(&test_subject)
             .execute(&db.pool)
             .await;
 
diff --git a/src/tests/users_tests.rs b/src/tests/users_tests.rs
index 529f024..369a03e 100644
--- a/src/tests/users_tests.rs
+++ b/src/tests/users_tests.rs
@@ -5,6 +5,7 @@ mod tests {
     use axum::http::StatusCode;
     use serde_json::json;
     use tower::util::ServiceExt;
+    use uuid;
 
     #[tokio::test]
     async fn test_list_users() {
@@ -302,77 +303,93 @@ mod tests {
     // OIDC Database Tests
     #[tokio::test]
     async fn test_create_oidc_user() {
-        let (app, container) = create_test_app().await;
+        let (_app, container) = create_test_app().await;
         let port = container.get_host_port_ipv4(5432).await.unwrap();
         let database_url = format!("postgresql://test:test@localhost:{}/test", port);
         let db = crate::db::Database::new(&database_url).await.unwrap();
 
+        // Generate random identifiers to avoid test interference
+        let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+        let test_username = format!("oidcuser_{}", test_id);
+        let test_email = format!("oidc_{}@example.com", test_id);
+        let test_subject = format!("oidc-subject-{}", test_id);
+
         let create_user = CreateUser {
-            username: "oidcuser".to_string(),
-            email: "oidc@example.com".to_string(),
+            username: test_username.clone(),
+            email: test_email.clone(),
             password: "".to_string(), // Not used for OIDC
             role: Some(UserRole::User),
         };
 
         let user = db.create_oidc_user(
             create_user,
-            "oidc-subject-123",
+            &test_subject,
             "https://provider.example.com",
             "oidc@example.com",
         ).await.unwrap();
 
-        assert_eq!(user.username, "oidcuser");
-        assert_eq!(user.email, "oidc@example.com");
-        assert_eq!(user.oidc_subject, Some("oidc-subject-123".to_string()));
+        assert_eq!(user.username, test_username);
+        assert_eq!(user.email, test_email);
+        assert_eq!(user.oidc_subject, Some(test_subject));
         assert_eq!(user.oidc_issuer, Some("https://provider.example.com".to_string()));
-        assert_eq!(user.oidc_email, Some("oidc@example.com".to_string()));
+        assert_eq!(user.oidc_email, Some(test_email.clone()));
         assert_eq!(user.auth_provider, AuthProvider::Oidc);
         assert!(user.password_hash.is_none());
     }
 
     #[tokio::test]
     async fn test_get_user_by_oidc_subject() {
-        let (app, container) = create_test_app().await;
+        let (_app, container) = create_test_app().await;
         let port = container.get_host_port_ipv4(5432).await.unwrap();
         let database_url = format!("postgresql://test:test@localhost:{}/test", port);
         let db = crate::db::Database::new(&database_url).await.unwrap();
 
+        // Generate random identifiers to avoid test interference
+        let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+        let test_username = format!("oidcuser_{}", test_id);
+        let test_email = format!("oidc_{}@example.com", test_id);
+        let test_subject = format!("oidc-subject-{}", test_id);
+
         // Create OIDC user
         let create_user = CreateUser {
-            username: "oidcuser2".to_string(),
-            email: "oidc2@example.com".to_string(),
+            username: test_username,
+            email: test_email.clone(),
             password: "".to_string(),
             role: Some(UserRole::User),
         };
 
         let created_user = db.create_oidc_user(
             create_user,
-            "oidc-subject-456",
+            &test_subject,
             "https://provider.example.com",
-            "oidc2@example.com",
+            &test_email,
         ).await.unwrap();
 
         // Retrieve by OIDC subject
         let found_user = db.get_user_by_oidc_subject(
-            "oidc-subject-456",
+            &test_subject,
             "https://provider.example.com"
         ).await.unwrap();
 
         assert!(found_user.is_some());
         let user = found_user.unwrap();
         assert_eq!(user.id, created_user.id);
-        assert_eq!(user.oidc_subject, Some("oidc-subject-456".to_string()));
+        assert_eq!(user.oidc_subject, Some(test_subject));
     }
 
     #[tokio::test]
     async fn test_get_user_by_oidc_subject_not_found() {
-        let (app, container) = create_test_app().await;
+        let (_app, container) = create_test_app().await;
         let port = container.get_host_port_ipv4(5432).await.unwrap();
         let database_url = format!("postgresql://test:test@localhost:{}/test", port);
         let db = crate::db::Database::new(&database_url).await.unwrap();
 
+        // Generate random subject that definitely doesn't exist
+        let test_id = uuid::Uuid::new_v4().to_string();
+        let nonexistent_subject = format!("nonexistent-subject-{}", test_id);
+        
         let found_user = db.get_user_by_oidc_subject(
-            "nonexistent-subject",
+            &nonexistent_subject,
             "https://provider.example.com"
         ).await.unwrap();
 
@@ -381,29 +398,35 @@ mod tests {
 
     #[tokio::test]
     async fn test_oidc_user_different_issuer() {
-        let (app, container) = create_test_app().await;
+        let (_app, container) = create_test_app().await;
         let port = container.get_host_port_ipv4(5432).await.unwrap();
         let database_url = format!("postgresql://test:test@localhost:{}/test", port);
         let db = crate::db::Database::new(&database_url).await.unwrap();
 
+        // Generate random identifiers to avoid test interference
+        let test_id = uuid::Uuid::new_v4().to_string()[..8].to_string();
+        let test_username = format!("oidcuser_{}", test_id);
+        let test_email = format!("oidc_{}@example.com", test_id);
+        let test_subject = format!("same-subject-{}", test_id);
+
         // Create OIDC user with one issuer
         let create_user = CreateUser {
-            username: "oidcuser3".to_string(),
-            email: "oidc3@example.com".to_string(),
+            username: test_username,
+            email: test_email.clone(),
             password: "".to_string(),
             role: Some(UserRole::User),
         };
 
         db.create_oidc_user(
             create_user,
-            "same-subject",
+            &test_subject,
             "https://provider1.example.com",
-            "oidc3@example.com",
+            &test_email,
         ).await.unwrap();
 
         // Try to find with different issuer (should not find)
         let found_user = db.get_user_by_oidc_subject(
-            "same-subject",
+            &test_subject,
             "https://provider2.example.com"
         ).await.unwrap();