diff --git a/lang/correctness/index_by_threadid.jl b/lang/correctness/index_by_threadid.jl
new file mode 100644
index 0000000..5fcdc5c
--- /dev/null
+++ b/lang/correctness/index_by_threadid.jl
@@ -0,0 +1,27 @@
+using Base.Threads: threadid, @threads
+
+states = zeros(10)
+Threads.@threads for i = 1:10
+    # ruleid: index-by-threadid
+    tid = Threads.threadid()
+    old_val = states[tid]
+    new_val = old_val + i
+    states[tid] = new_val
+end
+
+@threads for i = 1:10
+    # ruleid: index-by-threadid
+    tid = threadid()
+    val = states[tid]
+    states[tid] = val + 1
+end
+
+@threads :foo for i = 1:10
+    # ruleid: index-by-threadid
+    val = states[Threads.threadid()]
+end
+
+Threads.@threads :static for i = 1:10
+    # ok: index-by-threadid
+    val = states[Threads.threadid()]
+end
diff --git a/lang/correctness/index_by_threadid.yaml b/lang/correctness/index_by_threadid.yaml
new file mode 100644
index 0000000..9b4d6c5
--- /dev/null
+++ b/lang/correctness/index_by_threadid.yaml
@@ -0,0 +1,31 @@
+rules:
+  - id: index-by-threadid
+    patterns:
+      - pattern-inside: |
+          @threads ... for $X = ...
+            ...
+          end
+      - pattern-not-inside: |
+          @threads :static for $X = ...
+            ...
+          end
+      - pattern-either:
+          - pattern: $S[Threads.threadid()]
+          - pattern: $S[threadid()]
+          - pattern: |
+              $TID = Threads.threadid()
+              ...
+              $Y = $S[$TID]
+          - pattern: |
+              $TID = threadid()
+              ...
+              $Y = $S[$TID]
+    message: Indexing by `threadid()` may cause race conditions and should be avoided.
+    metadata:
+      confidence: LOW
+      references:
+        - https://www.julialang.org/blog/2023/07/PSA-dont-use-threadid/
+      license: LGPL
+    languages:
+      - julia
+    severity: WARNING