diff --git a/README.md b/README.md
index dc043ee..9122943 100644
--- a/README.md
+++ b/README.md
@@ -314,6 +314,11 @@ Returns VERITAS if a strict majority of the arguments are VERITAS, FALSITAS othe
 
 Returns the type of `value` as a string: `NVMERVS` (integer), `LITTERA` (string), `VERAX` (boolean), `CATALOGVS` (list), `FRACTIO` (fraction), `TABVLA` (dict), `FVNCTIO` (function), or `NVLLVS` (null).
 
+### DORMI
+`DORMI(n)`
+
+Sleeps for `n` seconds, where `n` is an integer, fraction, or NVLLVS (treated as 0). Returns nothing meaningful.
+
 ## Modules
 Modules are additions to the base `CENTVRION` syntax. They add or change certain features. Modules are included in your code by having
 
diff --git a/centvrion/ast_nodes.py b/centvrion/ast_nodes.py
index ef926e7..2bd341b 100644
--- a/centvrion/ast_nodes.py
+++ b/centvrion/ast_nodes.py
@@ -1,5 +1,6 @@
 import re
 import random
+import time
 from fractions import Fraction
 
 from rply.token import BaseBox
@@ -1128,6 +1129,18 @@ class BuiltIn(Node):
           ValFunc: "FVNCTIO", ValNul: "NVLLVS",
         }
         return vtable, ValStr(type_map[type(params[0])])
+      case "DORMI":
+        v = params[0]
+        if isinstance(v, ValNul):
+          seconds = 0
+        elif isinstance(v, ValInt):
+          seconds = v.value()
+        elif isinstance(v, ValFrac):
+          seconds = float(v.value())
+        else:
+          raise CentvrionError("DORMI requires a number or NVLLVS")
+        time.sleep(seconds)
+        return vtable, ValNul()
       case _:
         raise NotImplementedError(self.builtin)
 
diff --git a/centvrion/compiler/emit_expr.py b/centvrion/compiler/emit_expr.py
index 33dda29..105e2b6 100644
--- a/centvrion/compiler/emit_expr.py
+++ b/centvrion/compiler/emit_expr.py
@@ -258,6 +258,10 @@ def _emit_builtin(node, ctx):
     case "TYPVS":
       lines.append(f"CentValue {tmp} = cent_typvs({param_vars[0]});")
 
+    case "DORMI":
+      lines.append(f"cent_dormi({param_vars[0]});")
+      lines.append(f"CentValue {tmp} = cent_null();")
+
     case _:
       raise NotImplementedError(node.builtin)
 
diff --git a/centvrion/compiler/runtime/cent_runtime.c b/centvrion/compiler/runtime/cent_runtime.c
index 9b602fa..2e44ca0 100644
--- a/centvrion/compiler/runtime/cent_runtime.c
+++ b/centvrion/compiler/runtime/cent_runtime.c
@@ -559,6 +559,23 @@ CentValue cent_typvs(CentValue v) {
   return cent_str("IGNOTA"); /* unreachable */
 }
 
+void cent_dormi(CentValue n) {
+  struct timespec ts;
+  if (n.type == CENT_NULL) {
+    ts.tv_sec = 0; ts.tv_nsec = 0;
+  } else if (n.type == CENT_INT) {
+    ts.tv_sec = n.ival; ts.tv_nsec = 0;
+  } else if (n.type == CENT_FRAC) {
+    long sec = n.fval.num / n.fval.den;
+    long rem = n.fval.num % n.fval.den;
+    ts.tv_sec = sec;
+    ts.tv_nsec = rem * 1000000000L / n.fval.den;
+  } else {
+    cent_type_error("'DORMI' requires a number or NVLLVS");
+  }
+  nanosleep(&ts, NULL);
+}
+
 CentValue cent_fortis_numerus(CentValue lo, CentValue hi) {
   if (lo.type != CENT_INT || hi.type != CENT_INT)
     cent_type_error("'FORTIS_NVMERVS' requires two integers");
diff --git a/centvrion/compiler/runtime/cent_runtime.h b/centvrion/compiler/runtime/cent_runtime.h
index db1ae68..b0d9453 100644
--- a/centvrion/compiler/runtime/cent_runtime.h
+++ b/centvrion/compiler/runtime/cent_runtime.h
@@ -221,6 +221,7 @@ void      cent_semen(CentValue seed);                          /* SEMEN */
 void      cent_everro(void);                                   /* EVERRO */
 CentValue cent_senatus(CentValue *args, int n);                /* SENATVS */
 CentValue cent_typvs(CentValue v);                              /* TYPVS */
+void      cent_dormi(CentValue n);                              /* DORMI */
 
 /* ------------------------------------------------------------------ */
 /* Array helpers                                                        */
diff --git a/centvrion/lexer.py b/centvrion/lexer.py
index e55f22e..73b6fec 100644
--- a/centvrion/lexer.py
+++ b/centvrion/lexer.py
@@ -44,6 +44,7 @@ builtin_tokens = [("BUILTIN", i) for i in [
   "CLAVES",
   "DECIMATIO",
   "DICE",
+  "DORMI",
   "EVERRO",
   "FORTIS_NVMERVS",
   "FORTIS_ELECTIONIS",
diff --git a/tests.py b/tests.py
index e11437f..bfa245b 100644
--- a/tests.py
+++ b/tests.py
@@ -2,6 +2,7 @@ import os
 import random
 import subprocess
 import tempfile
+import time
 import unittest
 from io import StringIO
 from unittest.mock import patch
@@ -2217,5 +2218,93 @@ class TestFvnctio(unittest.TestCase):
     run_test(self, source, nodes, value, output)
 
 
+# --- DORMI ---
+
+dormi_tests = [
+  ("DORMI(NVLLVS)",
+    Program([], [ExpressionStatement(BuiltIn("DORMI", [Nullus()]))]),
+    ValNul()),
+]
+
+class TestDormi(unittest.TestCase):
+  @parameterized.expand(dormi_tests)
+  def test_dormi(self, source, nodes, value, output=""):
+    run_test(self, source, nodes, value, output)
+
+  def test_dormi_timing_int(self):
+    source = "DORMI(I)\n"
+    lexer = Lexer().get_lexer()
+    tokens = lexer.lex(source)
+    program = Parser().parse(tokens)
+
+    start = time.time()
+    program.eval()
+    elapsed = time.time() - start
+    self.assertAlmostEqual(elapsed, 1.0, delta=0.5)
+
+  def test_dormi_timing_int_compiled(self):
+    source = "DORMI(I)\n"
+    lexer = Lexer().get_lexer()
+    tokens = lexer.lex(source)
+    program = Parser().parse(tokens)
+
+    c_source = compile_program(program)
+    with tempfile.NamedTemporaryFile(suffix=".c", delete=False, mode="w") as tmp_c:
+      tmp_c.write(c_source)
+      tmp_c_path = tmp_c.name
+    with tempfile.NamedTemporaryFile(suffix="", delete=False) as tmp_bin:
+      tmp_bin_path = tmp_bin.name
+    try:
+      subprocess.run(
+        ["gcc", "-O2", tmp_c_path, _RUNTIME_C, "-o", tmp_bin_path],
+        check=True, capture_output=True,
+      )
+      start = time.time()
+      proc = subprocess.run([tmp_bin_path], capture_output=True, text=True)
+      elapsed = time.time() - start
+      self.assertEqual(proc.returncode, 0)
+      self.assertAlmostEqual(elapsed, 1.0, delta=0.5)
+    finally:
+      os.unlink(tmp_c_path)
+      os.unlink(tmp_bin_path)
+
+  def test_dormi_timing_frac(self):
+    source = "CVM FRACTIO\nDORMI(S)\n"
+    lexer = Lexer().get_lexer()
+    tokens = lexer.lex(source)
+    program = Parser().parse(tokens)
+
+    start = time.time()
+    program.eval()
+    elapsed = time.time() - start
+    self.assertAlmostEqual(elapsed, 0.5, delta=0.5)
+
+  def test_dormi_timing_frac_compiled(self):
+    source = "CVM FRACTIO\nDORMI(S)\n"
+    lexer = Lexer().get_lexer()
+    tokens = lexer.lex(source)
+    program = Parser().parse(tokens)
+
+    c_source = compile_program(program)
+    with tempfile.NamedTemporaryFile(suffix=".c", delete=False, mode="w") as tmp_c:
+      tmp_c.write(c_source)
+      tmp_c_path = tmp_c.name
+    with tempfile.NamedTemporaryFile(suffix="", delete=False) as tmp_bin:
+      tmp_bin_path = tmp_bin.name
+    try:
+      subprocess.run(
+        ["gcc", "-O2", tmp_c_path, _RUNTIME_C, "-o", tmp_bin_path],
+        check=True, capture_output=True,
+      )
+      start = time.time()
+      proc = subprocess.run([tmp_bin_path], capture_output=True, text=True)
+      elapsed = time.time() - start
+      self.assertEqual(proc.returncode, 0)
+      self.assertAlmostEqual(elapsed, 0.5, delta=0.5)
+    finally:
+      os.unlink(tmp_c_path)
+      os.unlink(tmp_bin_path)
+
+
 if __name__ == "__main__":
   unittest.main()