diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2123b687443..581812d91bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,6 +37,8 @@ release.
 
 ### Semantic Conventions
 
+- Add "IBM z/Architecture" (`s390x`) to `host.arch`
+  ([#2055](https://github.com/open-telemetry/opentelemetry-specification/pull/2055))
 - BREAKING: Remove db.cassandra.keyspace and db.hbase.namespace, and clarify db.name
   ([#1973](https://github.com/open-telemetry/opentelemetry-specification/pull/1973))
 - Add AWS App Runner as a cloud platform
diff --git a/semantic_conventions/resource/host.yaml b/semantic_conventions/resource/host.yaml
index b8cd3c2212a..e2893e6c3b5 100644
--- a/semantic_conventions/resource/host.yaml
+++ b/semantic_conventions/resource/host.yaml
@@ -43,6 +43,9 @@ groups:
             - id: ppc64
               value: 'ppc64'
               brief: "64-bit PowerPC"
+            - id: s390x
+              value: 's390x'
+              brief: "IBM z/Architecture"
             - id: x86
               value: 'x86'
               brief: "32-bit x86"
diff --git a/specification/resource/semantic_conventions/host.md b/specification/resource/semantic_conventions/host.md
index a151ba8843a..0bcb19093b5 100644
--- a/specification/resource/semantic_conventions/host.md
+++ b/specification/resource/semantic_conventions/host.md
@@ -27,5 +27,6 @@
 | `ia64` | Itanium |
 | `ppc32` | 32-bit PowerPC |
 | `ppc64` | 64-bit PowerPC |
+| `s390x` | IBM z/Architecture |
 | `x86` | 32-bit x86 |
 <!-- endsemconv -->