diff --git a/src/main/java/org/ays/admin_user/model/dto/request/AdminUserRegisterApplicationCompleteRequest.java b/src/main/java/org/ays/admin_user/model/dto/request/AdminUserRegisterApplicationCompleteRequest.java
index a16391b50..af3549e31 100644
--- a/src/main/java/org/ays/admin_user/model/dto/request/AdminUserRegisterApplicationCompleteRequest.java
+++ b/src/main/java/org/ays/admin_user/model/dto/request/AdminUserRegisterApplicationCompleteRequest.java
@@ -1,12 +1,12 @@
 package org.ays.admin_user.model.dto.request;
 
 import jakarta.validation.Valid;
-import jakarta.validation.constraints.Email;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.NotNull;
 import lombok.Getter;
 import lombok.Setter;
 import org.ays.common.model.dto.request.AysPhoneNumberRequest;
+import org.ays.common.util.validation.Email;
 import org.ays.common.util.validation.Name;
 
 /**
diff --git a/src/main/java/org/ays/common/util/validation/Email.java b/src/main/java/org/ays/common/util/validation/Email.java
new file mode 100644
index 000000000..4507a89a9
--- /dev/null
+++ b/src/main/java/org/ays/common/util/validation/Email.java
@@ -0,0 +1,39 @@
+package org.ays.common.util.validation;
+
+import jakarta.validation.Constraint;
+import jakarta.validation.Payload;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to validate email using {@link EmailValidator}.
+ */
+@Target(value = ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+@Constraint(validatedBy = EmailValidator.class)
+public @interface Email {
+
+    /**
+     * Returns the error message when email is not valid.
+     *
+     * @return the error message
+     */
+    String message() default "MUST BE VALID";
+
+    /**
+     * Returns the validation groups to which this constraint belongs.
+     *
+     * @return the validation groups
+     */
+    Class<?>[] groups() default {};
+
+    /**
+     * Returns the payload associated to this constraint.
+     *
+     * @return the payload
+     */
+    Class<? extends Payload>[] payload() default {};
+}
diff --git a/src/main/java/org/ays/common/util/validation/EmailValidator.java b/src/main/java/org/ays/common/util/validation/EmailValidator.java
new file mode 100644
index 000000000..0efedae30
--- /dev/null
+++ b/src/main/java/org/ays/common/util/validation/EmailValidator.java
@@ -0,0 +1,44 @@
+package org.ays.common.util.validation;
+
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
+import org.springframework.util.StringUtils;
+
+/**
+ * A custom validator implementation for the {@link Email} annotation.
+ * Validates whether the provided email invalid domain
+ * specified regular expression.
+ */
+class EmailValidator implements ConstraintValidator<Email, String> {
+
+    private static final String EMAIL_REGEX =
+            "^[a-zA-Z0-9çğıöşü._%+-]+[a-zA-Z0-9çğıöşü]+@[a-zA-Z0-9]+[.-]?[a-zA-Z0-9]+\\.[a-zA-Z]{2,}$";
+
+    /**
+     * Checks whether the given value is a valid email or not.
+     * <p>Some valid emails are:</p>
+     * <ul>
+     *     <li>user@example.com</li>
+     *     <li>john.doe123@example.co.uk</li>
+     *     <li>admin_123@example.org</li>
+     * </ul>
+     *
+     * <p>Some invalid emails are:</p>
+     * <ul>
+     *     <li>user@invalid</li>
+     *     <li>user@invalid!.com</li>
+     *     <li>user@.com</li>
+     * </ul>
+     *
+     * @param email object to validate
+     * @return true if the value is valid, false otherwise
+     */
+    @Override
+    public boolean isValid(String email, ConstraintValidatorContext constraintValidatorContext) {
+
+        if (!StringUtils.hasText(email)) {
+            return true;
+        }
+        return email.matches(EMAIL_REGEX);
+    }
+}
diff --git a/src/test/java/org/ays/admin_user/controller/AdminUserRegisterApplicationControllerTest.java b/src/test/java/org/ays/admin_user/controller/AdminUserRegisterApplicationControllerTest.java
index fe14ced60..3e436b753 100644
--- a/src/test/java/org/ays/admin_user/controller/AdminUserRegisterApplicationControllerTest.java
+++ b/src/test/java/org/ays/admin_user/controller/AdminUserRegisterApplicationControllerTest.java
@@ -450,6 +450,79 @@ void givenInvalidAdminUserRegisterApplicationCompleteRequestWithParametrizedInva
                 .completeRegistration(Mockito.anyString(), Mockito.any());
     }
 
+    @ParameterizedTest
+    @ValueSource(strings = {
+            "abc.def@mail.c",
+            "abc.def@mail#archive.com",
+            "abc.def@mail",
+            "abcdef@mail..com",
+            "abc-@mail.com"
+    })
+    void givenInvalidAdminUserRegisterApplicationCompleteRequestWithParametrizedInvalidEmails_whenEmailsAreNotValid_thenReturnValidationError(String invalidEmail) throws Exception {
+
+        // Given
+        String mockId = AysRandomUtil.generateUUID();
+        AdminUserRegisterApplicationCompleteRequest mockRequest = new AdminUserRegisterApplicationCompleteRequestBuilder()
+                .withValidFields()
+                .withEmail(invalidEmail)
+                .build();
+
+        // Then
+        String endpoint = BASE_PATH.concat("/registration-application/").concat(mockId).concat("/complete");
+        MockHttpServletRequestBuilder mockHttpServletRequestBuilder = AysMockMvcRequestBuilders
+                .post(endpoint, mockRequest);
+
+        AysError mockErrorResponse = AysErrorBuilder.VALIDATION_ERROR;
+
+        aysMockMvc.perform(mockHttpServletRequestBuilder, mockErrorResponse)
+                .andExpect(AysMockResultMatchersBuilders.status()
+                        .isBadRequest())
+                .andExpect(AysMockResultMatchersBuilders.subErrors()
+                        .isNotEmpty());
+
+        // Verify
+        Mockito.verify(adminUserRegisterService, Mockito.never())
+                .completeRegistration(Mockito.anyString(), Mockito.any());
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+            "abcdef@mail.com",
+            "abc+def@archive.com",
+            "john.doe123@example.co.uk",
+            "admin_123@example.org",
+            "admin-test@ays.com",
+            "üşengeç-birkız@mail.com"
+    })
+    void givenValidAdminUserRegisterApplicationCompleteRequestWithParametrizedValidEmails_whenEmailsAreValid_thenReturnSuccessResponse(String validEmail) throws Exception {
+        // Given
+        String mockId = AysRandomUtil.generateUUID();
+        AdminUserRegisterApplicationCompleteRequest mockRequest = new AdminUserRegisterApplicationCompleteRequestBuilder()
+                .withValidFields()
+                .withEmail(validEmail)
+                .build();
+
+        // When
+        Mockito.doNothing().when(adminUserRegisterService).completeRegistration(Mockito.anyString(), Mockito.any());
+
+        // Then
+        String endpoint = BASE_PATH.concat("/registration-application/").concat(mockId).concat("/complete");
+        MockHttpServletRequestBuilder mockHttpServletRequestBuilder = AysMockMvcRequestBuilders
+                .post(endpoint, mockRequest);
+
+        AysResponse<Void> mockResponse = AysResponseBuilder.SUCCESS;
+
+        aysMockMvc.perform(mockHttpServletRequestBuilder, mockResponse)
+                .andExpect(AysMockResultMatchersBuilders.status()
+                        .isOk())
+                .andExpect(AysMockResultMatchersBuilders.response()
+                        .doesNotExist());
+
+        // Verify
+        Mockito.verify(adminUserRegisterService, Mockito.times(1))
+                .completeRegistration(Mockito.anyString(), Mockito.any());
+    }
+
     @Test
     void givenValidAdminUserRegisterApplicationId_whenApproveAdminUserRegisterApplication_thenReturnNothing() throws Exception {
         // Given