diff --git a/script/util/run_tests.sh b/script/util/run_tests.sh
index df1f29db..c70bb4bf 100644
--- a/script/util/run_tests.sh
+++ b/script/util/run_tests.sh
@@ -27,7 +27,7 @@ function run_tests {
   local cmd="out/Debug/${target}"
   shift
 
-  while getopts "df:ghpv" option; do
+  while getopts "df:s:ghpv" option; do
     case ${option} in
       h)
         usage
@@ -48,6 +48,9 @@ function run_tests {
       v)
         args+=("--reporter=spec")
         ;;
+      s)
+        export TREE_SITTER_SEED=${OPTARG}
+        ;;
     esac
   done
 
diff --git a/spec/runtime/language_specs.cc b/spec/runtime/language_specs.cc
index d8d7f256..c902d35e 100644
--- a/spec/runtime/language_specs.cc
+++ b/spec/runtime/language_specs.cc
@@ -108,8 +108,6 @@ string random_words(size_t count) {
 START_TEST
 
 describe("Languages", [&]() {
-  srand(0);
-
   for (const auto &pair : languages) {
     describe(("The " + pair.first + " parser").c_str(), [&]() {
       TSDocument *doc;
@@ -117,6 +115,7 @@ describe("Languages", [&]() {
       before_each([&]() {
         doc = ts_document_make();
         ts_document_set_language(doc, pair.second);
+        // ts_document_set_debugger(doc, log_debugger_make(true));
       });
 
       after_each([&]() {
diff --git a/spec/runtime/runtime_specs.cc b/spec/runtime/runtime_specs.cc
index cf8c6937..d6540167 100644
--- a/spec/runtime/runtime_specs.cc
+++ b/spec/runtime/runtime_specs.cc
@@ -1,5 +1,16 @@
 #include "runtime/runtime_spec_helper.h"
 
 int main(int argc, char *argv[]) {
+  int seed;
+  const char *seed_env = getenv("TREE_SITTER_SEED");
+  if (seed_env) {
+    seed = atoi(seed_env);
+  } else {
+    seed = time(nullptr);
+  }
+
+  printf("Random seed: %d\n", seed);
+  srand(seed);
+
   return bandit::run(argc, argv);
 }