diff --git a/src/word_source/logical_words.c b/src/word_source/logical_words.c
index 07886ee..fcebf21 100644
--- a/src/word_source/logical_words.c
+++ b/src/word_source/logical_words.c
@@ -136,6 +136,54 @@ static void logical_word_invert(VM *vm) {
     vm_push(vm, ~n1);
 }
 
+/* LSHIFT ( x1 u -- x2 )  Logical left shift, u bits (FORTH-83 extension) */
+static void logical_word_lshift(VM *vm) {
+    if (vm->dsp < 1) {
+        log_message(LOG_ERROR, "LSHIFT: Stack underflow");
+        vm->error = 1;
+        return;
+    }
+
+    ucell_t u = (ucell_t) vm_pop(vm);
+    ucell_t x1 = (ucell_t) vm_pop(vm);
+
+    if (u >= (ucell_t)(sizeof(cell_t) * 8)) {
+        log_message(LOG_ERROR, "LSHIFT: shift count %lu out of range", (unsigned long) u);
+        vm->error = 1;
+        return;
+    }
+
+    cell_t result = (cell_t)(x1 << u);
+
+    vm_push(vm, result);
+
+    log_message(LOG_DEBUG, "LSHIFT: %lu << %lu = %ld", (unsigned long) x1, (unsigned long) u, (long) result);
+}
+
+/* RSHIFT ( x1 u -- x2 )  Logical right shift, u bits (FORTH-83 extension) */
+static void logical_word_rshift(VM *vm) {
+    if (vm->dsp < 1) {
+        log_message(LOG_ERROR, "RSHIFT: Stack underflow");
+        vm->error = 1;
+        return;
+    }
+
+    ucell_t u = (ucell_t) vm_pop(vm);
+    ucell_t x1 = (ucell_t) vm_pop(vm);
+
+    if (u >= (ucell_t)(sizeof(cell_t) * 8)) {
+        log_message(LOG_ERROR, "RSHIFT: shift count %lu out of range", (unsigned long) u);
+        vm->error = 1;
+        return;
+    }
+
+    cell_t result = (cell_t)(x1 >> u);
+
+    vm_push(vm, result);
+
+    log_message(LOG_DEBUG, "RSHIFT: %lu >> %lu = %ld", (unsigned long) x1, (unsigned long) u, (long) result);
+}
+
 /* 0= - Test for zero ( n -- flag ) */
 static void logical_word_zero_equals(VM *vm) {
     if (vm->dsp < 0) {
@@ -376,6 +424,8 @@ void register_logical_words(VM *vm) {
     register_word(vm, "XOR", logical_word_xor);
     register_word(vm, "NOT", logical_word_not);
     register_word(vm, "INVERT", logical_word_invert);
+    register_word(vm, "LSHIFT", logical_word_lshift);
+    register_word(vm, "RSHIFT", logical_word_rshift);
 
     /* Zero comparisons */
     register_word(vm, "0=", logical_word_zero_equals);