diff --git a/src/executor/valgrind/measure.rs b/src/executor/valgrind/measure.rs
index 32196009..1a8e16ff 100644
--- a/src/executor/valgrind/measure.rs
+++ b/src/executor/valgrind/measure.rs
@@ -46,7 +46,8 @@ fn get_valgrind_args(tool: &SimulationTool, config: &ExecutorConfig) -> Vec<Stri
         }
     }
 
-    let children_skip_patterns = ["*esbuild"];
+    // Valgrind changes argv[0] when tracing Nix's rustup wrapper, which breaks rustup proxy detection.
+    let children_skip_patterns = ["*esbuild", "*.rustup-wrapped"];
     args.push(format!(
         "--trace-children-skip={}",
         children_skip_patterns.join(",")
@@ -235,6 +236,18 @@ mod tests {
         (script_status, out_status)
     }
 
+    #[test]
+    fn test_valgrind_skips_rustup_wrapped_proxy() {
+        let config = ExecutorConfig::test();
+        let args = get_valgrind_args(&SimulationTool::Callgrind, &config);
+        let skip_arg = args
+            .iter()
+            .find(|arg| arg.starts_with("--trace-children-skip="))
+            .unwrap();
+
+        assert!(skip_arg.contains("*.rustup-wrapped"));
+    }
+
     #[test]
     fn test_run_wrapper_script() {
         temp_env::with_var("TEST_ENV_VAR", "test_value".into(), || {