diff --git a/.fernignore b/.fernignore
index a54fbc537..3289beafa 100644
--- a/.fernignore
+++ b/.fernignore
@@ -15,3 +15,5 @@ src/main/java/com/merge/legacy
 src/main/java/com/merge/api/core/QueryStringMapper.java
 
 src/test/java/com/merge/api/integration/CursorPaginationIntegrationTest.java
+src/main/java/com/merge/api/core/ClientOptions.java
+src/test/java/com/merge/api/core/ClientOptionsTest.java
diff --git a/src/main/java/com/merge/api/core/ClientOptions.java b/src/main/java/com/merge/api/core/ClientOptions.java
index 430519cf1..4c56c2e61 100644
--- a/src/main/java/com/merge/api/core/ClientOptions.java
+++ b/src/main/java/com/merge/api/core/ClientOptions.java
@@ -148,11 +148,13 @@ public ClientOptions build() {
                     this.httpClient != null ? this.httpClient.newBuilder() : new OkHttpClient.Builder();
 
             if (this.httpClient != null) {
-                timeout.ifPresent(timeout -> httpClientBuilder
-                        .callTimeout(timeout, TimeUnit.SECONDS)
+                // Apply timeout configuration even when using custom client to ensure consistent behavior
+                int timeoutValue = this.timeout.orElse(60);
+                httpClientBuilder
+                        .callTimeout(timeoutValue, TimeUnit.SECONDS)
                         .connectTimeout(0, TimeUnit.SECONDS)
                         .writeTimeout(0, TimeUnit.SECONDS)
-                        .readTimeout(0, TimeUnit.SECONDS));
+                        .readTimeout(0, TimeUnit.SECONDS);
             } else {
                 httpClientBuilder
                         .callTimeout(this.timeout.orElse(60), TimeUnit.SECONDS)
diff --git a/src/test/java/com/merge/api/core/ClientOptionsTest.java b/src/test/java/com/merge/api/core/ClientOptionsTest.java
new file mode 100644
index 000000000..1a6a1f858
--- /dev/null
+++ b/src/test/java/com/merge/api/core/ClientOptionsTest.java
@@ -0,0 +1,135 @@
+package com.merge.api.core;
+
+import okhttp3.OkHttpClient;
+import org.junit.jupiter.api.Test;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class ClientOptionsTest {
+
+    @Test
+    public void testDefaultClientTimeouts() {
+        // Test: No custom client, no explicit timeout -> uses 60s default
+        ClientOptions options = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .build();
+
+        OkHttpClient client = options.httpClient();
+        assertEquals(60, client.callTimeoutMillis() / 1000);
+        assertEquals(0, client.connectTimeoutMillis());
+        assertEquals(0, client.readTimeoutMillis());
+        assertEquals(0, client.writeTimeoutMillis());
+    }
+
+    @Test
+    public void testDefaultClientWithExplicitTimeout() {
+        // Test: No custom client, explicit timeout -> uses explicit timeout
+        ClientOptions options = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .timeout(120)
+                .build();
+
+        OkHttpClient client = options.httpClient();
+        assertEquals(120, client.callTimeoutMillis() / 1000);
+        assertEquals(0, client.connectTimeoutMillis());
+        assertEquals(0, client.readTimeoutMillis());
+        assertEquals(0, client.writeTimeoutMillis());
+    }
+
+    @Test
+    public void testCustomClientWithoutExplicitTimeout() {
+        // Test: Custom client with OkHttp defaults, no explicit SDK timeout -> uses 60s default
+        OkHttpClient customClient = new OkHttpClient.Builder().build();
+
+        ClientOptions options = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .httpClient(customClient)
+                .build();
+
+        OkHttpClient client = options.httpClient();
+        assertEquals(60, client.callTimeoutMillis() / 1000);
+        assertEquals(0, client.connectTimeoutMillis());
+        assertEquals(0, client.readTimeoutMillis());
+        assertEquals(0, client.writeTimeoutMillis());
+    }
+
+    @Test
+    public void testCustomClientWithExplicitTimeout() {
+        // Test: Custom client with explicit SDK timeout -> uses explicit timeout
+        OkHttpClient customClient = new OkHttpClient.Builder().build();
+
+        ClientOptions options = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .httpClient(customClient)
+                .timeout(90)
+                .build();
+
+        OkHttpClient client = options.httpClient();
+        assertEquals(90, client.callTimeoutMillis() / 1000);
+        assertEquals(0, client.connectTimeoutMillis());
+        assertEquals(0, client.readTimeoutMillis());
+        assertEquals(0, client.writeTimeoutMillis());
+    }
+
+    @Test
+    public void testCustomClientOverridesOriginalTimeouts() {
+        // Test: Custom client with different timeouts -> SDK overrides them
+        OkHttpClient customClient = new OkHttpClient.Builder()
+                .callTimeout(30, TimeUnit.SECONDS)
+                .connectTimeout(15, TimeUnit.SECONDS)
+                .readTimeout(20, TimeUnit.SECONDS)
+                .writeTimeout(25, TimeUnit.SECONDS)
+                .build();
+
+        ClientOptions options = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .httpClient(customClient)
+                .timeout(120)
+                .build();
+
+        OkHttpClient client = options.httpClient();
+        // SDK should override all timeouts
+        assertEquals(120, client.callTimeoutMillis() / 1000);
+        assertEquals(0, client.connectTimeoutMillis());
+        assertEquals(0, client.readTimeoutMillis());
+        assertEquals(0, client.writeTimeoutMillis());
+    }
+
+    @Test
+    public void testTimeoutConsistencyBetweenCustomAndDefaultClients() {
+        // Test: Both custom and default clients should have same timeout behavior
+
+        // Default client
+        ClientOptions defaultOptions = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .build();
+
+        // Custom client
+        OkHttpClient customClient = new OkHttpClient.Builder().build();
+        ClientOptions customOptions = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .httpClient(customClient)
+                .build();
+
+        OkHttpClient defaultHttpClient = defaultOptions.httpClient();
+        OkHttpClient customHttpClient = customOptions.httpClient();
+
+        // Both should have same timeout configuration
+        assertEquals(defaultHttpClient.callTimeoutMillis(), customHttpClient.callTimeoutMillis());
+        assertEquals(defaultHttpClient.connectTimeoutMillis(), customHttpClient.connectTimeoutMillis());
+        assertEquals(defaultHttpClient.readTimeoutMillis(), customHttpClient.readTimeoutMillis());
+        assertEquals(defaultHttpClient.writeTimeoutMillis(), customHttpClient.writeTimeoutMillis());
+    }
+
+    @Test
+    public void testTimeoutReflectedInClientOptionsTimeout() {
+        // Test: ClientOptions.timeout() method returns actual client timeout
+        ClientOptions options = ClientOptions.builder()
+                .environment(Environment.PRODUCTION)
+                .timeout(75)
+                .build();
+
+        assertEquals(75, options.timeout(null));
+    }
+}
\ No newline at end of file