diff --git a/src/main/java/org/opensearch/knn/common/KNNConstants.java b/src/main/java/org/opensearch/knn/common/KNNConstants.java
index fdbe0bb20..46d429fcc 100644
--- a/src/main/java/org/opensearch/knn/common/KNNConstants.java
+++ b/src/main/java/org/opensearch/knn/common/KNNConstants.java
@@ -35,6 +35,9 @@ public class KNNConstants {
     public static final String MODEL_TIMESTAMP = "timestamp";
     public static final String MODEL_DESCRIPTION = "description";
     public static final String MODEL_ERROR = "error";
+    public static final String PARAM_SIZE = "size";
+    public static final Integer SEARCH_MODEL_MIN_SIZE = 1;
+    public static final Integer SEARCH_MODEL_MAX_SIZE = 1000;
 
     public static final String KNN_THREAD_POOL_PREFIX = "knn";
     public static final String TRAIN_THREAD_POOL = "training";
diff --git a/src/main/java/org/opensearch/knn/plugin/rest/RestSearchModelHandler.java b/src/main/java/org/opensearch/knn/plugin/rest/RestSearchModelHandler.java
index eeb510b9d..675e3c1d1 100644
--- a/src/main/java/org/opensearch/knn/plugin/rest/RestSearchModelHandler.java
+++ b/src/main/java/org/opensearch/knn/plugin/rest/RestSearchModelHandler.java
@@ -30,6 +30,9 @@
 import java.util.function.IntConsumer;
 
 import static org.opensearch.knn.common.KNNConstants.MODELS;
+import static org.opensearch.knn.common.KNNConstants.PARAM_SIZE;
+import static org.opensearch.knn.common.KNNConstants.SEARCH_MODEL_MAX_SIZE;
+import static org.opensearch.knn.common.KNNConstants.SEARCH_MODEL_MIN_SIZE;
 
 /**
  * Rest Handler for search model api endpoint.
@@ -69,9 +72,30 @@ private void checkUnSupportedParamsExists(RestRequest request) {
         throw new IllegalArgumentException(errorMessage);
     }
 
+    private void validateSizeParameter(RestRequest request) {
+        if (!request.hasParam(PARAM_SIZE)) {
+            return;
+        }
+        if (isSearchSizeValueValid(request.paramAsInt(PARAM_SIZE, 1))) {
+            return;
+        }
+        throw new IllegalArgumentException(
+            String.format("%s must be between %d and %d inclusive", PARAM_SIZE, SEARCH_MODEL_MIN_SIZE, SEARCH_MODEL_MAX_SIZE)
+        );
+    }
+
+    private boolean isSearchSizeValueValid(int searchSize) {
+        return (searchSize >= SEARCH_MODEL_MIN_SIZE) && (searchSize <= SEARCH_MODEL_MAX_SIZE);
+    }
+
+    private void validateRequest(RestRequest request) {
+        checkUnSupportedParamsExists(request);
+        validateSizeParameter(request);
+    }
+
     @Override
     protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
-        checkUnSupportedParamsExists(request);
+        validateRequest(request);
         SearchRequest searchRequest = new SearchRequest();
         IntConsumer setSize = size -> searchRequest.source().size(size);
         request.withContentOrSourceParamParserOrNull(
diff --git a/src/test/java/org/opensearch/knn/plugin/action/RestSearchModelHandlerIT.java b/src/test/java/org/opensearch/knn/plugin/action/RestSearchModelHandlerIT.java
index 8137f50a1..d65f434f6 100644
--- a/src/test/java/org/opensearch/knn/plugin/action/RestSearchModelHandlerIT.java
+++ b/src/test/java/org/opensearch/knn/plugin/action/RestSearchModelHandlerIT.java
@@ -36,6 +36,9 @@
 import java.util.Map;
 
 import static org.opensearch.knn.common.KNNConstants.MODELS;
+import static org.opensearch.knn.common.KNNConstants.PARAM_SIZE;
+import static org.opensearch.knn.common.KNNConstants.SEARCH_MODEL_MAX_SIZE;
+import static org.opensearch.knn.common.KNNConstants.SEARCH_MODEL_MIN_SIZE;
 
 /**
  * Integration tests to check the correctness of {@link org.opensearch.knn.plugin.rest.RestSearchModelHandler}
@@ -76,6 +79,23 @@ public void testNoModelExists() throws IOException {
 
     }
 
+    public void testSizeValidationFailsInvalidSize() throws IOException {
+        createModelSystemIndex();
+        for (Integer invalidSize : Arrays.asList(SEARCH_MODEL_MIN_SIZE - 1, SEARCH_MODEL_MAX_SIZE + 1)) {
+            String restURI = String.join("/", KNNPlugin.KNN_BASE_URI, MODELS, "_search?" + PARAM_SIZE + "=" + invalidSize);
+            Request request = new Request("GET", restURI);
+
+            ResponseException ex = expectThrows(ResponseException.class, () -> client().performRequest(request));
+            assertTrue(
+                ex.getMessage()
+                    .contains(
+                        String.format("%s must be between %d and %d inclusive", PARAM_SIZE, SEARCH_MODEL_MIN_SIZE, SEARCH_MODEL_MAX_SIZE)
+                    )
+            );
+        }
+
+    }
+
     public void testSearchModelExists() throws IOException {
         createModelSystemIndex();
         createIndex("irrelevant-index", Settings.EMPTY);