diff --git a/android/guava/src/com/google/common/net/HttpHeaders.java b/android/guava/src/com/google/common/net/HttpHeaders.java
index adbd216c6d01..54d39919bf4b 100644
--- a/android/guava/src/com/google/common/net/HttpHeaders.java
+++ b/android/guava/src/com/google/common/net/HttpHeaders.java
@@ -365,6 +365,16 @@ private ReferrerPolicyValues() {}
    */
   public static final String SOURCE_MAP = "SourceMap";
 
+  /**
+   * The HTTP <a href="https://github.com/WICG/nav-speculation/blob/main/opt-in.md">{@code
+   * Supports-Loading-Mode}</a> header field name. This can be used to specify, for example, <a
+   * href="https://developer.chrome.com/docs/privacy-sandbox/fenced-frame/#server-opt-in">fenced
+   * frames</a>.
+   *
+   * @since NEXT
+   */
+  public static final String SUPPORTS_LOADING_MODE = "Supports-Loading-Mode";
+
   /**
    * The HTTP <a href="http://tools.ietf.org/html/rfc6797#section-6.1">{@code
    * Strict-Transport-Security}</a> header field name.
diff --git a/guava/src/com/google/common/net/HttpHeaders.java b/guava/src/com/google/common/net/HttpHeaders.java
index adbd216c6d01..54d39919bf4b 100644
--- a/guava/src/com/google/common/net/HttpHeaders.java
+++ b/guava/src/com/google/common/net/HttpHeaders.java
@@ -365,6 +365,16 @@ private ReferrerPolicyValues() {}
    */
   public static final String SOURCE_MAP = "SourceMap";
 
+  /**
+   * The HTTP <a href="https://github.com/WICG/nav-speculation/blob/main/opt-in.md">{@code
+   * Supports-Loading-Mode}</a> header field name. This can be used to specify, for example, <a
+   * href="https://developer.chrome.com/docs/privacy-sandbox/fenced-frame/#server-opt-in">fenced
+   * frames</a>.
+   *
+   * @since NEXT
+   */
+  public static final String SUPPORTS_LOADING_MODE = "Supports-Loading-Mode";
+
   /**
    * The HTTP <a href="http://tools.ietf.org/html/rfc6797#section-6.1">{@code
    * Strict-Transport-Security}</a> header field name.