diff --git a/src/main/java/com/example/solidconnection/application/service/ApplicationSubmissionService.java b/src/main/java/com/example/solidconnection/application/service/ApplicationSubmissionService.java
index 753bc89cc..0f22be85f 100644
--- a/src/main/java/com/example/solidconnection/application/service/ApplicationSubmissionService.java
+++ b/src/main/java/com/example/solidconnection/application/service/ApplicationSubmissionService.java
@@ -68,7 +68,7 @@ public boolean submitScore(String email, ScoreRequest scoreRequest) {
      * */
     @Transactional
     public boolean submitUniversityChoice(String email, UniversityChoiceRequest universityChoiceRequest) {
-        validateNoDuplicateUniversityChoices(universityChoiceRequest);
+        validateUniversityChoices(universityChoiceRequest);
 
         // 성적 제출한 적이 한번도 없는 경우
         Application existingApplication = applicationRepository.findTop1BySiteUser_EmailOrderByTermDesc(email)
@@ -83,14 +83,16 @@ public boolean submitUniversityChoice(String email, UniversityChoiceRequest univ
                 })
                 .orElse(existingApplication); // 금학기에 이미 성적 제출한 경우 기존 객체 사용
 
+        validateUpdateLimitNotExceed(application);
+
         UniversityInfoForApply firstChoiceUniversity = universityInfoForApplyRepository
                 .getUniversityInfoForApplyByIdAndTerm(universityChoiceRequest.firstChoiceUniversityId(), term);
-        UniversityInfoForApply secondChoiceUniversity = universityInfoForApplyRepository
-                .getUniversityInfoForApplyByIdAndTerm(universityChoiceRequest.secondChoiceUniversityId(), term);
-        UniversityInfoForApply thirdChoiceUniversity = universityInfoForApplyRepository
-                .getUniversityInfoForApplyByIdAndTerm(universityChoiceRequest.thirdChoiceUniversityId(), term);
-
-        validateUpdateLimitNotExceed(application);
+        UniversityInfoForApply secondChoiceUniversity = Optional.ofNullable(universityChoiceRequest.secondChoiceUniversityId())
+                .map(id -> universityInfoForApplyRepository.getUniversityInfoForApplyByIdAndTerm(id, term))
+                .orElse(null);
+        UniversityInfoForApply thirdChoiceUniversity = Optional.ofNullable(universityChoiceRequest.thirdChoiceUniversityId())
+                .map(id -> universityInfoForApplyRepository.getUniversityInfoForApplyByIdAndTerm(id, term))
+                .orElse(null);
         application.updateUniversityChoice(firstChoiceUniversity, secondChoiceUniversity, thirdChoiceUniversity, getRandomNickname());
         return true;
     }
@@ -109,14 +111,21 @@ private void validateUpdateLimitNotExceed(Application application) {
         }
     }
 
-    private void validateNoDuplicateUniversityChoices(UniversityChoiceRequest universityChoiceRequest) {
+    // 입력값 유효성 검증
+    private void validateUniversityChoices(UniversityChoiceRequest universityChoiceRequest) {
         Set<Long> uniqueUniversityIds = new HashSet<>();
-
         uniqueUniversityIds.add(universityChoiceRequest.firstChoiceUniversityId());
-        uniqueUniversityIds.add(universityChoiceRequest.secondChoiceUniversityId());
-        uniqueUniversityIds.add(universityChoiceRequest.thirdChoiceUniversityId());
+        if (universityChoiceRequest.secondChoiceUniversityId() != null) {
+            addUniversityChoice(uniqueUniversityIds, universityChoiceRequest.secondChoiceUniversityId());
+        }
+        if (universityChoiceRequest.thirdChoiceUniversityId() != null) {
+            addUniversityChoice(uniqueUniversityIds, universityChoiceRequest.thirdChoiceUniversityId());
+        }
+    }
 
-        if (uniqueUniversityIds.size() < 3) {
+    private void addUniversityChoice(Set<Long> uniqueUniversityIds, Long universityId) {
+        boolean notAdded = !uniqueUniversityIds.add(universityId);
+        if (notAdded) {
             throw new CustomException(CANT_APPLY_FOR_SAME_UNIVERSITY);
         }
     }
diff --git a/src/test/java/com/example/solidconnection/unit/service/ApplicationServiceTest.java b/src/test/java/com/example/solidconnection/unit/service/ApplicationServiceTest.java
index d967c90bf..7688478fc 100644
--- a/src/test/java/com/example/solidconnection/unit/service/ApplicationServiceTest.java
+++ b/src/test/java/com/example/solidconnection/unit/service/ApplicationServiceTest.java
@@ -16,6 +16,8 @@
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
@@ -23,6 +25,7 @@
 
 import java.util.Optional;
 
+import static com.example.solidconnection.custom.exception.ErrorCode.CANT_APPLY_FOR_SAME_UNIVERSITY;
 import static com.example.solidconnection.custom.exception.ErrorCode.SCORE_SHOULD_SUBMITTED_FIRST;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -116,7 +119,9 @@ private Application createApplication(String term) {
         verify(applicationRepository, times(0)).save(any(Application.class));
     }
 
-    // 예외테스트
+    /**
+     * 지망대학 제출
+     */
     @Test
     void 지망대학_제출할_때_성적_제출이력이_없다면_예외_응답을_반환한다() {
         // given
@@ -171,4 +176,48 @@ private Application createApplication(String term) {
         verify(siteUserRepository, times(0)).getByEmail(siteUser.getEmail());
         verify(applicationRepository, times(0)).save(any(Application.class));
     }
+
+    @ParameterizedTest
+    @CsvSource({
+            "1, 2, 3",
+            "1, , 3",
+            "1, 2, ",
+            "1, , "
+    })
+    void 지망대학_제출할_때_2지망과_3지망은_NULL_허용한다(Long firstChoice, Long secondChoice, Long thirdChoice) {
+        // Given
+        UniversityChoiceRequest universityChoiceRequest = new UniversityChoiceRequest(firstChoice, secondChoice, thirdChoice);
+        when(applicationRepository.findTop1BySiteUser_EmailOrderByTermDesc(siteUser.getEmail()))
+                .thenReturn(Optional.of(application));
+
+        // When
+        applicationSubmissionService.submitUniversityChoice(siteUser.getEmail(), universityChoiceRequest);
+
+        // Then
+        verify(applicationRepository, times(1)).findTop1BySiteUser_EmailOrderByTermDesc(siteUser.getEmail());
+        verify(siteUserRepository, times(0)).getByEmail(siteUser.getEmail());
+        verify(applicationRepository, times(0)).save(any(Application.class));
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+            "1, 1, 1",
+            "1, 2, 1",
+            "1, 1, 2",
+            "1, , 1",
+            "1, 1, "
+    })
+    void 지망대학_제출할_때_선택지가_중복된다면_예외_응답을_반환한다(Long firstChoice, Long secondChoice, Long thirdChoice) {
+        // given
+        UniversityChoiceRequest universityChoiceRequest = new UniversityChoiceRequest(firstChoice, secondChoice, thirdChoice);
+
+        // when, then
+        CustomException exception = assertThrows(CustomException.class, () -> {
+            applicationSubmissionService.submitUniversityChoice(siteUser.getEmail(), universityChoiceRequest);
+        });
+        assertThat(exception.getMessage())
+                .isEqualTo(CANT_APPLY_FOR_SAME_UNIVERSITY.getMessage());
+        assertThat(exception.getCode())
+                .isEqualTo(CANT_APPLY_FOR_SAME_UNIVERSITY.getCode());
+    }
 }