diff --git a/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/Constants.java b/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/Constants.java
index 9ac034a89d5b..4e12bcdcbdc1 100644
--- a/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/Constants.java
+++ b/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/Constants.java
@@ -20,8 +20,12 @@
 
 /** A class that holds all constants for vertexai/generativeai. */
 public final class Constants {
+  public static final String MODEL_NAME_PREFIX_PROJECTS = "projects/";
+  public static final String MODEL_NAME_PREFIX_PUBLISHERS = "publishers/";
+  public static final String MODEL_NAME_PREFIX_MODELS = "models/";
   public static final ImmutableSet<String> MODEL_NAME_PREFIXES =
-      ImmutableSet.of("publishers/google/models/", "models/");
+      ImmutableSet.of(
+          MODEL_NAME_PREFIX_PROJECTS, MODEL_NAME_PREFIX_PUBLISHERS, MODEL_NAME_PREFIX_MODELS);
 
   private Constants() {}
 }
diff --git a/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/GenerativeModel.java b/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/GenerativeModel.java
index 5a1d3d9a56f3..db5a6ab7cb6d 100644
--- a/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/GenerativeModel.java
+++ b/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/GenerativeModel.java
@@ -99,12 +99,9 @@ private GenerativeModel(
     checkNotNull(safetySettings, "ImmutableList<SafetySettings> can't be null.");
     checkNotNull(tools, "ImmutableList<Tool> can't be null.");
 
-    modelName = reconcileModelName(modelName);
-    this.modelName = modelName;
-    this.resourceName =
-        String.format(
-            "projects/%s/locations/%s/publishers/google/models/%s",
-            vertexAi.getProjectId(), vertexAi.getLocation(), modelName);
+    this.resourceName = getResourceName(modelName, vertexAi);
+    // reconcileModelName should be called after getResourceName.
+    this.modelName = reconcileModelName(modelName);
     this.vertexAi = vertexAi;
     this.generationConfig = generationConfig;
     this.safetySettings = safetySettings;
@@ -157,7 +154,7 @@ public Builder setModelName(String modelName) {
               + " https://cloud.google.com/vertex-ai/docs/generative-ai/learn/models#gemini-models"
               + " to find the right model name.");
 
-      this.modelName = reconcileModelName(modelName);
+      this.modelName = modelName;
       return this;
     }
 
@@ -584,10 +581,28 @@ public ChatSession startChat() {
   private static String reconcileModelName(String modelName) {
     for (String prefix : Constants.MODEL_NAME_PREFIXES) {
       if (modelName.startsWith(prefix)) {
-        modelName = modelName.substring(prefix.length());
+        modelName = modelName.substring(modelName.lastIndexOf('/') + 1);
         break;
       }
     }
     return modelName;
   }
+
+  /**
+   * Computes resourceName based on original modelName. Note: this should happen before the
+   * modelName is reconciled.
+   */
+  private static String getResourceName(String modelName, VertexAI vertexAi) {
+    if (modelName.startsWith(Constants.MODEL_NAME_PREFIX_PROJECTS)) {
+      return modelName;
+    } else if (modelName.startsWith(Constants.MODEL_NAME_PREFIX_PUBLISHERS)) {
+      return String.format(
+          "projects/%s/locations/%s/%s",
+          vertexAi.getProjectId(), vertexAi.getLocation(), modelName);
+    } else {
+      return String.format(
+          "projects/%s/locations/%s/publishers/google/models/%s",
+          vertexAi.getProjectId(), vertexAi.getLocation(), reconcileModelName(modelName));
+    }
+  }
 }
diff --git a/java-vertexai/google-cloud-vertexai/src/test/java/com/google/cloud/vertexai/generativeai/GenerativeModelTest.java b/java-vertexai/google-cloud-vertexai/src/test/java/com/google/cloud/vertexai/generativeai/GenerativeModelTest.java
index c52f3be380ba..1df2354b6d96 100644
--- a/java-vertexai/google-cloud-vertexai/src/test/java/com/google/cloud/vertexai/generativeai/GenerativeModelTest.java
+++ b/java-vertexai/google-cloud-vertexai/src/test/java/com/google/cloud/vertexai/generativeai/GenerativeModelTest.java
@@ -108,9 +108,7 @@ public final class GenerativeModelTest {
                   .setVertexAiSearch(
                       VertexAISearch.newBuilder()
                           .setDatastore(
-                              String.format(
-                                  "projects/%s/locations/%s/collections/%s/dataStores/%s",
-                                  PROJECT, "global", "default_collection", "test_123")))
+                              "projects/test_project/locations/global/collections/default_collection/dataStores/test_123"))
                   .setDisableAttribution(false))
           .build();
 
@@ -164,6 +162,19 @@ public void testInstantiateGenerativeModel() {
     assertThat(model.getTools()).isEmpty();
   }
 
+  @Test
+  public void
+      testInstantiateGenerativeModel_withModelNameStartingFromProjects_modelNameIsCorrect() {
+    model =
+        new GenerativeModel(
+            "projects/test_project/locations/test_location/publishers/google/models/gemini-pro",
+            vertexAi);
+    assertThat(model.getModelName()).isEqualTo(MODEL_NAME);
+    assertThat(model.getGenerationConfig()).isEqualTo(GenerationConfig.getDefaultInstance());
+    assertThat(model.getSafetySettings()).isEmpty();
+    assertThat(model.getTools()).isEmpty();
+  }
+
   @Test
   public void testInstantiateGenerativeModelwithBuilder() {
     model = new GenerativeModel.Builder().setModelName(MODEL_NAME).setVertexAi(vertexAi).build();
@@ -286,6 +297,32 @@ public void testGenerateContentwithText() throws Exception {
         ArgumentCaptor.forClass(GenerateContentRequest.class);
     verify(mockUnaryCallable).call(request.capture());
     assertThat(request.getValue().getContents(0).getParts(0).getText()).isEqualTo(TEXT);
+    assertThat(request.getValue().getModel())
+        .isEqualTo(
+            "projects/test_project/locations/test_location/publishers/google/models/gemini-pro");
+  }
+
+  @Test
+  public void testGenerateContentwithText_withFullModelName_requestHasCorrectResourceName()
+      throws Exception {
+    model =
+        new GenerativeModel(
+            "projects/another_project/locations/europe-west4/publishers/google/models/another_model",
+            vertexAi);
+
+    when(mockPredictionServiceClient.generateContentCallable()).thenReturn(mockUnaryCallable);
+    when(mockUnaryCallable.call(any(GenerateContentRequest.class)))
+        .thenReturn(mockGenerateContentResponse);
+
+    GenerateContentResponse unused = model.generateContent(TEXT);
+
+    ArgumentCaptor<GenerateContentRequest> request =
+        ArgumentCaptor.forClass(GenerateContentRequest.class);
+    verify(mockUnaryCallable).call(request.capture());
+    assertThat(request.getValue().getModel())
+        .isEqualTo(
+            "projects/another_project/locations/europe-west4/publishers/google/models/another_model");
+    assertThat(request.getValue().getContents(0).getParts(0).getText()).isEqualTo(TEXT);
   }
 
   @Test