diff --git a/app/Jobs/UserCreateJob.php b/app/Jobs/UserCreateJob.php
index 42c0742a..e875eda5 100644
--- a/app/Jobs/UserCreateJob.php
+++ b/app/Jobs/UserCreateJob.php
@@ -33,7 +33,7 @@ public function handle() {
             'verified' => $this->verified,
         ]);
 
-        $latest = TermsOfUseVersion::latestActiveVersion();
+        $latest = TermsOfUseVersion::getActiveVersion();
         if ($latest) {
             UserTermsOfUseAcceptance::create([
                 'user_id' => $user->id,
diff --git a/app/Jobs/UserTouAcceptanceJob.php b/app/Jobs/UserTouAcceptanceJob.php
index 964d3ff4..6bdcff45 100644
--- a/app/Jobs/UserTouAcceptanceJob.php
+++ b/app/Jobs/UserTouAcceptanceJob.php
@@ -28,7 +28,7 @@ public function handle(): void {
             try {
                 UserTermsOfUseAcceptance::create([
                     'user_id' => $user->id,
-                    'tou_version' => TermsOfUseVersion::latestActiveVersion()->version,
+                    'tou_version' => TermsOfUseVersion::getActiveVersion()->version,
                     'tou_accepted_at' => $user->created_at,
                 ]);
             } catch (Throwable $exception) {
diff --git a/app/TermsOfUseVersion.php b/app/TermsOfUseVersion.php
index e4472407..ada1b1f6 100644
--- a/app/TermsOfUseVersion.php
+++ b/app/TermsOfUseVersion.php
@@ -29,7 +29,26 @@ class TermsOfUseVersion extends Model {
         'active' => 'boolean',
     ];
 
-    public static function latestActiveVersion(): ?self {
-        return self::query()->where('active', true)->latest()->first();
+    /**
+     * Get the active ToU version.
+     */
+    public static function getActiveVersion(): ?self {
+        return self::query()->where('active', true)->first();
+    }
+
+    /**
+     * Ensure only one ToU version remains active after any save operation.
+     */
+    protected static function booted(): void {
+        static::saving(function (self $model): void {
+            if (!$model->active) {
+                return;
+            }
+
+            self::query()
+                ->where('version', '!=', $model->version)
+                ->where('active', true)
+                ->update(['active' => false]);
+        });
     }
 }
diff --git a/tests/Jobs/UserTermsOfUseAcceptanceTest.php b/tests/Jobs/UserTermsOfUseAcceptanceTest.php
index ddbf70ec..cc431d8b 100644
--- a/tests/Jobs/UserTermsOfUseAcceptanceTest.php
+++ b/tests/Jobs/UserTermsOfUseAcceptanceTest.php
@@ -19,14 +19,14 @@ public function testUserCreationCreatesTouAcceptance(): void {
 
         $this->assertDatabaseHas('tou_acceptances', [
             'user_id' => $user->id,
-            'tou_version' => TermsOfUseVersion::latestActiveVersion()->version,
+            'tou_version' => TermsOfUseVersion::getActiveVersion()->version,
         ]);
 
         $rows = UserTermsOfUseAcceptance::where('user_id', $user->id)->get();
         $this->assertCount(1, $rows);
         $acceptance = $rows->first();
 
-        $this->assertSame(TermsOfUseVersion::latestActiveVersion()->version, $acceptance->tou_version);
+        $this->assertSame(TermsOfUseVersion::getActiveVersion()->version, $acceptance->tou_version);
         $this->assertNotNull($acceptance->tou_accepted_at);
     }
 }
diff --git a/tests/Jobs/UserTouAcceptanceJobTest.php b/tests/Jobs/UserTouAcceptanceJobTest.php
index 5f804ca5..e7a846e5 100644
--- a/tests/Jobs/UserTouAcceptanceJobTest.php
+++ b/tests/Jobs/UserTouAcceptanceJobTest.php
@@ -26,7 +26,7 @@ public function testTouAcceptanceJob(): void {
         (new CreateFirstTermsOfUseVersionJob)->handle();
         (new UserTouAcceptanceJob)->handle();
 
-        $latest = TermsOfUseVersion::latestActiveVersion()->version;
+        $latest = TermsOfUseVersion::getActiveVersion()->version;
 
         $this->assertDatabaseHas('tou_acceptances', ['user_id' => $u1->id, 'tou_version' => $latest]);
         $this->assertDatabaseHas('tou_acceptances', ['user_id' => $u2->id, 'tou_version' => $latest]);
diff --git a/tests/Models/TermsOfUseVersionTest.php b/tests/Models/TermsOfUseVersionTest.php
new file mode 100644
index 00000000..bba866e4
--- /dev/null
+++ b/tests/Models/TermsOfUseVersionTest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Tests\Models;
+
+use App\TermsOfUseVersion;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class TermsOfUseVersionTest extends TestCase {
+    use RefreshDatabase;
+
+    public function testSavingActiveVersionDeactivatesOtherVersions(): void {
+        $first = TermsOfUseVersion::create([
+            'version' => '2024-01-01',
+            'active' => true,
+        ]);
+
+        $second = TermsOfUseVersion::create([
+            'version' => '2025-01-01',
+            'active' => true,
+        ]);
+
+        $this->assertFalse($first->fresh()->active);
+        $this->assertTrue($second->fresh()->active);
+    }
+
+    public function testSavingInactiveVersionDoesNotAffectExistingActiveVersion(): void {
+        $active = TermsOfUseVersion::create([
+            'version' => '2024-03-01',
+            'active' => true,
+        ]);
+
+        TermsOfUseVersion::create([
+            'version' => '2024-04-01',
+            'active' => false,
+        ]);
+
+        $this->assertTrue($active->fresh()->active);
+    }
+}