diff --git a/sentry_sdk/tracing_utils.py b/sentry_sdk/tracing_utils.py
index c2e34a795b..f4929ef1a7 100644
--- a/sentry_sdk/tracing_utils.py
+++ b/sentry_sdk/tracing_utils.py
@@ -1113,6 +1113,9 @@ def span_decorator(f: "Any") -> "Any":
         """
         Decorator to create a span for the given function.
         """
+        new_attributes = dict(attributes) if attributes else {}
+        if "sentry.op" not in new_attributes:
+            new_attributes["sentry.op"] = OP.FUNCTION
 
         @functools.wraps(f)
         async def async_wrapper(*args: "Any", **kwargs: "Any") -> "Any":
@@ -1127,7 +1130,7 @@ async def async_wrapper(*args: "Any", **kwargs: "Any") -> "Any":
             span_name = name or qualname_from_function(f) or ""
 
             with start_streaming_span(
-                name=span_name, attributes=attributes, active=active
+                name=span_name, attributes=new_attributes, active=active
             ):
                 result = await f(*args, **kwargs)
                 return result
@@ -1150,7 +1153,7 @@ def sync_wrapper(*args: "Any", **kwargs: "Any") -> "Any":
             span_name = name or qualname_from_function(f) or ""
 
             with start_streaming_span(
-                name=span_name, attributes=attributes, active=active
+                name=span_name, attributes=new_attributes, active=active
             ):
                 return f(*args, **kwargs)
 
diff --git a/tests/tracing/test_decorator.py b/tests/tracing/test_decorator.py
index d6f6ca87ed..9852d950ab 100644
--- a/tests/tracing/test_decorator.py
+++ b/tests/tracing/test_decorator.py
@@ -110,6 +110,7 @@ def traced_function():
         span["name"]
         == "test_decorator.test_trace_decorator_span_streaming.<locals>.traced_function"
     )
+    assert span["attributes"]["sentry.op"] == "function"
     assert span["status"] == "ok"
 
 
@@ -136,6 +137,7 @@ def traced_function():
 
     assert span["name"] == "traced"
     assert span["attributes"]["traced.attribute"] == 123
+    assert span["attributes"]["sentry.op"] == "function"
     assert span["status"] == "ok"
 
 
@@ -193,6 +195,7 @@ async def traced_function():
         span["name"]
         == "test_decorator.test_trace_decorator_async_span_streaming.<locals>.traced_function"
     )
+    assert span["attributes"]["sentry.op"] == "function"
     assert span["status"] == "ok"
 
 
@@ -222,6 +225,7 @@ async def traced_function():
 
     assert span["name"] == "traced"
     assert span["attributes"]["traced.attribute"] == 123
+    assert span["attributes"]["sentry.op"] == "function"
     assert span["status"] == "ok"