diff --git a/src/script_opt/FuncInfo.cc b/src/script_opt/FuncInfo.cc
index 2516d1bd44..545f278f96 100644
--- a/src/script_opt/FuncInfo.cc
+++ b/src/script_opt/FuncInfo.cc
@@ -431,6 +431,7 @@ static std::unordered_map<std::string, unsigned int> func_attrs = {
     {"skip_further_processing", ATTR_NO_SCRIPT_SIDE_EFFECTS},
     {"skip_http_entity_data", ATTR_NO_SCRIPT_SIDE_EFFECTS},
     {"skip_smtp_data", ATTR_NO_SCRIPT_SIDE_EFFECTS},
+    {"sleep", ATTR_NO_SCRIPT_SIDE_EFFECTS},
     {"split_string", ATTR_FOLDABLE},
     {"split_string1", ATTR_FOLDABLE},
     {"split_string_all", ATTR_FOLDABLE},
diff --git a/src/zeek.bif b/src/zeek.bif
index ee14c0ddce..fbcf322c44 100644
--- a/src/zeek.bif
+++ b/src/zeek.bif
@@ -600,6 +600,27 @@ function piped_exec%(program: string, to_write: string%): bool
 	return zeek::val_mgr->True();
 	%}
 
+## Sleeps for the given amount of time.
+##
+## i: The time interval to sleep for.
+##
+## Returns: The :zeek:type:`interval` Zeek actually slept for.
+##
+## .. note::
+##
+##      This is a blocking sleep! Zeek will not run most of its processing
+##      during that time. You almost certainly DO NOT WANT THIS outside
+##      of specific testing/troubleshooting scenarios. To sleep asynchronously,
+##      :zeek:see:`schedule` an event, or consider :zeek:id:`Exec::run`.
+function sleep%(i: interval%): interval
+	%{
+	const auto start = std::chrono::high_resolution_clock::now();
+	std::this_thread::sleep_for(std::chrono::duration<double>(i));
+	const auto end = std::chrono::high_resolution_clock::now();
+	const auto slept = std::chrono::duration<double>(end - start).count();
+	return zeek::make_intrusive<zeek::IntervalVal>(slept);
+        %}
+
 %%{
 #include "zeek/OpaqueVal.h"
 %%}
diff --git a/testing/btest/Baseline.zam/opt.ZAM-bif-tracking/output b/testing/btest/Baseline.zam/opt.ZAM-bif-tracking/output
index 6f645f9525..0138aa7bfe 100644
--- a/testing/btest/Baseline.zam/opt.ZAM-bif-tracking/output
+++ b/testing/btest/Baseline.zam/opt.ZAM-bif-tracking/output
@@ -1,2 +1,2 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-539 seen BiFs, 0 unseen BiFs (), 0 new BiFs ()
+540 seen BiFs, 0 unseen BiFs (), 0 new BiFs ()
diff --git a/testing/btest/Baseline/bifs.sleep/out b/testing/btest/Baseline/bifs.sleep/out
new file mode 100644
index 0000000000..49d861c74c
--- /dev/null
+++ b/testing/btest/Baseline/bifs.sleep/out
@@ -0,0 +1 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
diff --git a/testing/btest/bifs/sleep.zeek b/testing/btest/bifs/sleep.zeek
new file mode 100644
index 0000000000..7fbd3e6b46
--- /dev/null
+++ b/testing/btest/bifs/sleep.zeek
@@ -0,0 +1,21 @@
+# Verifies sleep()'s reported latencies.
+#
+# @TEST-EXEC: zeek -b %INPUT 2>out
+# @TEST-EXEC: btest-diff out
+
+function test_sleep(i: interval)
+	{
+	local start = current_time();
+	local sleep_delay = sleep(i);
+	local script_delay = current_time() - start;
+
+	assert script_delay >= i, fmt("sleep() took %s, less than %s", script_delay, i);
+	assert sleep_delay >= i, fmt("slept for %s, less than %s", script_delay, i);
+	assert sleep_delay <= script_delay, fmt("sleep() claims %s, longer than %s", sleep_delay, script_delay);
+	}
+
+event zeek_init()
+	{
+	test_sleep(100msec);
+	test_sleep(1sec);
+	}
diff --git a/testing/btest/opt/ZAM-bif-tracking.zeek b/testing/btest/opt/ZAM-bif-tracking.zeek
index 627c21f444..e059f1f839 100644
--- a/testing/btest/opt/ZAM-bif-tracking.zeek
+++ b/testing/btest/opt/ZAM-bif-tracking.zeek
@@ -464,6 +464,7 @@ global known_BiFs = set(
 	"skip_further_processing",
 	"skip_http_entity_data",
 	"skip_smtp_data",
+	"sleep",
 	"sort",
 	"split_string",
 	"split_string1",