diff --git a/gc.c b/gc.c
index a8b1fdbd..593d45ed 100644
--- a/gc.c
+++ b/gc.c
@@ -322,6 +322,7 @@ void sexp_reset_weak_references(sexp ctx) {
 #define sexp_reset_weak_references(ctx)
 #endif
 
+#if SEXP_USE_FINALIZERS
 sexp sexp_finalize (sexp ctx) {
   size_t size;
   sexp p, t, end;
@@ -368,6 +369,7 @@ sexp sexp_finalize (sexp ctx) {
 #endif
   return sexp_make_fixnum(finalize_count);
 }
+#endif
 
 sexp sexp_sweep (sexp ctx, size_t *sum_freed_ptr) {
   size_t freed, max_freed=0, sum_freed=0, size;
diff --git a/include/chibi/features.h b/include/chibi/features.h
index d0a0efdf..35d658d7 100644
--- a/include/chibi/features.h
+++ b/include/chibi/features.h
@@ -84,6 +84,11 @@
 /*   go away and you're not working on your own C extension. */
 /* #define SEXP_USE_CONSERVATIVE_GC 1 */
 
+/* uncomment this to disable automatic running of finalizers */
+/*   You will need to close ports and file descriptors manually */
+/*   (as you should anyway) and some C extensions may break. */
+/* #define SEXP_USE_FINALIZERS 0 */
+
 /* uncomment this to add additional native checks to only mark objects in the heap */
 /* #define SEXP_USE_SAFE_GC_MARK 1 */
 
@@ -387,6 +392,10 @@
 #define SEXP_USE_CONSERVATIVE_GC 0
 #endif
 
+#ifndef SEXP_USE_FINALIZERS
+#define SEXP_USE_FINALIZERS 1
+#endif
+
 #ifndef SEXP_USE_TRACK_ALLOC_SOURCE
 #define SEXP_USE_TRACK_ALLOC_SOURCE SEXP_USE_DEBUG_GC > 2
 #endif
diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 88e4c13d..fa7bbc90 100755
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -1522,7 +1522,11 @@ SEXP_API int sexp_grow_heap (sexp ctx, size_t size, size_t chunk_size);
 SEXP_API sexp_heap sexp_make_heap (size_t size, size_t max_size, size_t chunk_size);
 SEXP_API void sexp_mark (sexp ctx, sexp x);
 SEXP_API sexp sexp_sweep (sexp ctx, size_t *sum_freed_ptr);
+#if SEXP_USE_FINALIZERS
 SEXP_API sexp sexp_finalize (sexp ctx);
+#else
+#define sexp_finalize(ctx) SEXP_ZERO
+#endif
 #endif
 
 #if SEXP_USE_GLOBAL_HEAP
diff --git a/tests/build/build-opts.txt b/tests/build/build-opts.txt
index a22b3c57..4dfc2197 100644
--- a/tests/build/build-opts.txt
+++ b/tests/build/build-opts.txt
@@ -5,6 +5,7 @@ CPPFLAGS=-DSEXP_USE_SIMPLIFY=0
 CPPFLAGS=-DSEXP_USE_TYPE_DEFS=0
 SEXP_USE_BOEHM=1;CPPFLAGS=-I/opt/local/include;LDFLAGS=-L/opt/local/lib
 CPPFLAGS=-DSEXP_USE_DEBUG_GC=1
+CPPFLAGS=-DSEXP_USE_FINALIZERS=0
 CPPFLAGS=-DSEXP_USE_CONSERVATIVE_GC=1
 CPPFLAGS=-DSEXP_USE_GLOBAL_HEAP=1
 CPPFLAGS=-DSEXP_USE_GLOBAL_SYMBOLS=1