diff --git a/ack-script/acknowledgements.html b/ack-script/acknowledgements.html
index 48989562..dc37a1df 100644
--- a/ack-script/acknowledgements.html
+++ b/ack-script/acknowledgements.html
@@ -1,7 +1,19 @@
 <section id="ack" class="appendix informative">
     <h2>Acknowledgements</h2>
+
+    <h3>In Memoriam</h3>
+    <p>Gregg Kellogg was a central figure in the story of JSON-LD. He worked
+    tirelessly on JSON-LD and many other specifications for more than a decade,
+    right up until his death on September 6th, 2025. Gregg’s passion for solving
+    hard problems with finesse was only exceeded by his willingness to collaborate
+    with and encourage others in reaching that destination. The JSON-LD and
+    broader Linked Data communities will be forever grateful for Gregg’s
+    consistent, careful, and kindly delivered contributions during their most
+    formative years.</p>
+
+    <h3>Contributions</h3>
     <p>
-        The editors would like to specially thank the following individuals for making significant
+        The editors would like to especially thank the following individuals for making significant
         contributions to the authoring and editing of this specification:
     </p>