diff --git a/CHANGELOG.md b/CHANGELOG.md
index a47b02f1..cdac3a6a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Performance
 - Faster runtime-error detection: single `case` glob instead of 23-iteration loop in `detect_runtime_error` (#668)
+- Hot-path coverage flag now cached in `_BASHUNIT_COVERAGE_ON`, removing a function dispatch per call (#664)
 
 ## [0.36.0](https://github.com/TypedDevs/bashunit/compare/0.35.0...0.36.0) - 2026-05-07
 
diff --git a/src/runner.sh b/src/runner.sh
index be5cdcbf..c3a76ed1 100755
--- a/src/runner.sh
+++ b/src/runner.sh
@@ -12,6 +12,17 @@ function bashunit::runner::restore_workdir() {
   cd "$BASHUNIT_WORKING_DIR" 2>/dev/null || true
 }
 
+# Caches BASHUNIT_COVERAGE into _BASHUNIT_COVERAGE_ON ("1"|"0") so hot-path checks
+# avoid a function dispatch per call. Call once after arg parsing; tests that
+# toggle BASHUNIT_COVERAGE mid-run must call this again to refresh.
+function bashunit::runner::sync_coverage_flag() {
+  if [ "${BASHUNIT_COVERAGE-}" = "true" ]; then
+    _BASHUNIT_COVERAGE_ON=1
+  else
+    _BASHUNIT_COVERAGE_ON=0
+  fi
+}
+
 function bashunit::runner::source_login_shell_profiles() {
   # shellcheck disable=SC1091
   [ -f /etc/profile ] && source /etc/profile 2>/dev/null || true
@@ -27,7 +38,7 @@ function bashunit::runner::export_test_identity() {
   local test_file=$1
   local fn_name=$2
   export BASHUNIT_CURRENT_TEST_ID="$(bashunit::helper::generate_id "$fn_name")"
-  if bashunit::env::is_coverage_enabled; then
+  if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
     export _BASHUNIT_COVERAGE_CURRENT_TEST_FILE="$test_file"
     export _BASHUNIT_COVERAGE_CURRENT_TEST_FN="$fn_name"
   fi
@@ -167,8 +178,10 @@ function bashunit::runner::load_test_files() {
   local -a scripts_ids=()
   local scripts_ids_count=0
 
+  bashunit::runner::sync_coverage_flag
+
   # Initialize coverage tracking if enabled
-  if bashunit::env::is_coverage_enabled; then
+  if [ "$_BASHUNIT_COVERAGE_ON" = 1 ]; then
     # Auto-discover coverage paths if not explicitly set
     if [ -z "$BASHUNIT_COVERAGE_PATHS" ]; then
       BASHUNIT_COVERAGE_PATHS=$(bashunit::coverage::auto_discover_paths "${files[@]}")
@@ -737,7 +750,7 @@ function bashunit::runner::run_test() {
     fi
 
     # Enable coverage tracking early to include set_up/tear_down hooks
-    if bashunit::env::is_coverage_enabled; then
+    if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
       bashunit::coverage::enable_trap
     fi
 
@@ -941,7 +954,7 @@ function bashunit::runner::cleanup_on_exit() {
   local exit_code="$2"
 
   # Disable coverage trap before cleanup to avoid interference
-  if bashunit::env::is_coverage_enabled; then
+  if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
     bashunit::coverage::disable_trap
   fi
 
@@ -1381,7 +1394,7 @@ function bashunit::runner::run_set_up_before_script() {
   start_time=$(bashunit::clock::now)
 
   # Enable coverage trap to attribute lines executed during set_up_before_script
-  if bashunit::env::is_coverage_enabled; then
+  if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
     bashunit::coverage::enable_trap
   fi
 
@@ -1390,7 +1403,7 @@ function bashunit::runner::run_set_up_before_script() {
   local status=$?
 
   # Disable coverage trap after hook execution
-  if bashunit::env::is_coverage_enabled; then
+  if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
     bashunit::coverage::disable_trap
   fi
 
@@ -1520,7 +1533,7 @@ function bashunit::runner::run_tear_down_after_script() {
   start_time=$(bashunit::clock::now)
 
   # Enable coverage trap to attribute lines executed during tear_down_after_script
-  if bashunit::env::is_coverage_enabled; then
+  if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
     bashunit::coverage::enable_trap
   fi
 
@@ -1529,7 +1542,7 @@ function bashunit::runner::run_tear_down_after_script() {
   local status=$?
 
   # Disable coverage trap after hook execution
-  if bashunit::env::is_coverage_enabled; then
+  if [ "${_BASHUNIT_COVERAGE_ON:-0}" = 1 ]; then
     bashunit::coverage::disable_trap
   fi
 
diff --git a/tests/unit/runner_test.sh b/tests/unit/runner_test.sh
index eff156b0..0e8745d9 100644
--- a/tests/unit/runner_test.sh
+++ b/tests/unit/runner_test.sh
@@ -48,6 +48,33 @@ function test_extract_assertion_runtime_output_keeps_user_output_that_looks_like
   assert_same "✗ Failed: emitted by the code under test" "$actual"
 }
 
+function test_sync_coverage_flag_sets_one_when_enabled() {
+  local _orig="${BASHUNIT_COVERAGE-}"
+  BASHUNIT_COVERAGE="true"
+  bashunit::runner::sync_coverage_flag
+  assert_same "1" "$_BASHUNIT_COVERAGE_ON"
+  BASHUNIT_COVERAGE="$_orig"
+  bashunit::runner::sync_coverage_flag
+}
+
+function test_sync_coverage_flag_sets_zero_when_disabled() {
+  local _orig="${BASHUNIT_COVERAGE-}"
+  BASHUNIT_COVERAGE="false"
+  bashunit::runner::sync_coverage_flag
+  assert_same "0" "$_BASHUNIT_COVERAGE_ON"
+  BASHUNIT_COVERAGE="$_orig"
+  bashunit::runner::sync_coverage_flag
+}
+
+function test_sync_coverage_flag_sets_zero_when_unset() {
+  local _orig="${BASHUNIT_COVERAGE-}"
+  unset BASHUNIT_COVERAGE
+  bashunit::runner::sync_coverage_flag
+  assert_same "0" "$_BASHUNIT_COVERAGE_ON"
+  BASHUNIT_COVERAGE="$_orig"
+  bashunit::runner::sync_coverage_flag
+}
+
 function test_detect_runtime_error_returns_empty_when_input_is_empty() {
   local actual
   actual="$(bashunit::runner::detect_runtime_error "")"