diff --git a/src/tools/miri/ci.sh b/src/tools/miri/ci.sh
index a8aae524e710..3146ef41a3bb 100755
--- a/src/tools/miri/ci.sh
+++ b/src/tools/miri/ci.sh
@@ -52,7 +52,7 @@ function run_tests {
 
     # Also run some many-seeds tests. 64 seeds means this takes around a minute per test.
     for FILE in tests/many-seeds/*.rs; do
-      MIRI_SEEDS=64 CARGO_EXTRA_FLAGS="$CARGO_EXTRA_FLAGS -q" ./miri many-seeds ./miri run "$FILE"
+      MIRI_SEEDS=64 ./miri many-seeds ./miri run "$FILE"
     done
 
     # Check that the benchmarks build and run, but without actually benchmarking.
diff --git a/src/tools/miri/miri b/src/tools/miri/miri
index c816a4bb06b1..938df9799da3 100755
--- a/src/tools/miri/miri
+++ b/src/tools/miri/miri
@@ -2,5 +2,5 @@
 set -e
 # Instead of doing just `cargo run --manifest-path .. $@`, we invoke miri-script binary directly. Invoking `cargo run` goes through
 # rustup (that sets it's own environmental variables), which is undesirable.
-cargo build -q --manifest-path "$(dirname "$0")"/miri-script/Cargo.toml
+cargo build $CARGO_EXTRA_FLAGS -q --manifest-path "$(dirname "$0")"/miri-script/Cargo.toml
 "$(dirname "$0")"/miri-script/target/debug/miri-script "$@"
diff --git a/src/tools/miri/miri-script/src/commands.rs b/src/tools/miri/miri-script/src/commands.rs
index ebaef1fd475e..cadd7ade4a5f 100644
--- a/src/tools/miri/miri-script/src/commands.rs
+++ b/src/tools/miri/miri-script/src/commands.rs
@@ -319,6 +319,8 @@ impl Command {
         let Some((program_name, args)) = hyperfine.split_first() else {
             bail!("expected HYPERFINE environment variable to be non-empty");
         };
+        // Extra flags to pass to cargo.
+        let cargo_extra_flags = std::env::var("CARGO_EXTRA_FLAGS").unwrap_or_default();
         // Make sure we have an up-to-date Miri installed and selected the right toolchain.
         Self::install(vec![])?;
 
@@ -341,7 +343,7 @@ impl Command {
             // That seems to make Windows CI happy.
             cmd!(
                 sh,
-                "{program_name} {args...} 'cargo miri run --manifest-path \"'{current_bench}'\"'"
+                "{program_name} {args...} 'cargo miri run '{cargo_extra_flags}' --manifest-path \"'{current_bench}'\"'"
             )
             .run()?;
         }
diff --git a/src/tools/miri/test-cargo-miri/run-test.py b/src/tools/miri/test-cargo-miri/run-test.py
index ca2f69fc8cfa..db4341169ea3 100755
--- a/src/tools/miri/test-cargo-miri/run-test.py
+++ b/src/tools/miri/test-cargo-miri/run-test.py
@@ -15,12 +15,14 @@ CGREEN  = '\33[32m'
 CBOLD   = '\33[1m'
 CEND    = '\33[0m'
 
+CARGO_EXTRA_FLAGS = os.environ.get("CARGO_EXTRA_FLAGS", "").split()
+
 def fail(msg):
     print("\nTEST FAIL: {}".format(msg))
     sys.exit(1)
 
 def cargo_miri(cmd, quiet = True):
-    args = ["cargo", "miri", cmd]
+    args = ["cargo", "miri", cmd] + CARGO_EXTRA_FLAGS
     if quiet:
         args += ["-q"]
     if 'MIRI_TEST_TARGET' in os.environ:
diff --git a/src/tools/miri/tests/compiletest.rs b/src/tools/miri/tests/compiletest.rs
index 8b97c8bb83c8..78dd3df01ec5 100644
--- a/src/tools/miri/tests/compiletest.rs
+++ b/src/tools/miri/tests/compiletest.rs
@@ -16,6 +16,11 @@ fn get_host() -> String {
         .host
 }
 
+pub fn flagsplit(flags: &str) -> Vec<String> {
+    // This code is taken from `RUSTFLAGS` handling in cargo.
+    flags.split(' ').map(str::trim).filter(|s| !s.is_empty()).map(str::to_string).collect()
+}
+
 // Build the shared object file for testing external C function calls.
 fn build_so_for_c_ffi_tests() -> PathBuf {
     let cc = option_env!("CC").unwrap_or("cc");
@@ -100,14 +105,16 @@ fn test_config(target: &str, path: &str, mode: Mode, with_dependencies: bool) ->
     if with_dependencies && use_std {
         config.dependencies_crate_manifest_path =
             Some(Path::new("test_dependencies").join("Cargo.toml"));
-        config.dependency_builder.args = vec![
-            "run".into(),
+        let mut builder_args = vec!["run".into()];
+        builder_args.extend(flagsplit(&env::var("CARGO_EXTRA_FLAGS").unwrap_or_default()));
+        builder_args.extend([
             "--manifest-path".into(),
             "cargo-miri/Cargo.toml".into(),
             "--".into(),
             "miri".into(),
             "run".into(), // There is no `cargo miri build` so we just use `cargo miri run`.
-        ];
+        ]);
+        config.dependency_builder.args = builder_args.into_iter().map(Into::into).collect();
     }
     config
 }