diff --git a/.changelog/5183.changed b/.changelog/5183.changed
new file mode 100644
index 0000000000..e59614bf63
--- /dev/null
+++ b/.changelog/5183.changed
@@ -0,0 +1 @@
+`opentelemetry-sdk`: tighten `ReadableSpan.attributes` return type to non-Optional `Mapping`
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py
index 9cdfebeb47..1901afabbd 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py
@@ -492,7 +492,8 @@ def status(self) -> trace_api.Status:
         return self._status
 
     @property
-    def attributes(self) -> types.Attributes:
+    def attributes(self) -> Mapping[str, types.AttributeValue]:
+        # `or {}` keeps the return non-None; see #4569.
         return MappingProxyType(self._attributes or {})
 
     @property