diff --git a/Makefile.in b/Makefile.in
index 56e7fc5..ca9164f 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -24,10 +24,11 @@ LFLAGS = @COVERAGE_LFLAGS@
 TEST_CFLAGS = @CFLAGS@ @CHECK_CFLAGS@
 TEST_LFLAGS = @CHECK_LIBS@ @COVERAGE_LFLAGS@
 
-OBJECTS = transliteration.o czech.o hindi.o utf8.o velthuis.o
+OBJECTS = transliteration.o czech.o hindi.o utf8.o velthuis.o harvard-kyoto.o
 
 TEST_OBJECTS = tests/main.o tests/translit.o tests/czech.o		\
-	tests/hindi.o tests/velthuis.o tests/utf8.o tests/integration.o
+	tests/hindi.o tests/velthuis.o tests/harvard-kyoto.o		\
+	tests/utf8.o tests/integration.o
 
 AUX_FILES = Makefile configure aclocal.m4 install-sh config.h* *.log	\
 	*.status *.cache
diff --git a/harvard-kyoto.c b/harvard-kyoto.c
new file mode 100644
index 0000000..0320bb3
--- /dev/null
+++ b/harvard-kyoto.c
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* https://en.wikipedia.org/wiki/Velthuis */
+
+#include "compat.h"
+#include "harvard-kyoto.h"
+#include "utf8.h"
+
+struct encoder_tuple {
+	const char *from;
+	const char *to;
+};
+
+static const struct encoder_tuple table[] = {
+	{"A",  "\u0101"},
+	{"I",  "\u012b"},
+	{"U",  "\u016b"},
+	{"RR", "\u1e5d"},
+	{"R",  "\u1e5b"},
+	{"LL", "\u1e39"},
+	{"L",  "\u1e37"},
+
+	{"aa",  "\u0101"},
+	{"ii",  "\u012b"},
+	{"uu",  "\u016b"},
+	{".rr", "\u1e5d"},
+	{".r",  "\u1e5b"},
+	{".ll", "\u1e39"},
+	{".l",  "\u1e37"},
+
+	{"M",  "\u1e43"},
+	{"H",  "\u1e25"},
+
+	{"G",  "\u1e45"},
+	{"J",  "\u00f1"},
+	{"T",  "\u1e6d"},
+	{"D",  "\u1e0d"},
+	{"N",  "\u1e47"},
+	{"S",  "\u1e63"},
+	{"sh", "\u015b"},
+	{"z",  "\u015b"}
+};
+
+static const struct encoder_tuple *find_tuple(const char *text)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(table); i++) {
+		if (strncmp(text, table[i].from, strlen(table[i].from)) == 0) {
+			return &table[i];
+		}
+	}
+
+	return NULL;
+}
+
+int encode_harvard_kyoto_to_iast(const char *text, char **out)
+{
+	const char *str = text, *end = str + strlen(str);
+	const struct encoder_tuple *tuple;
+	char *buf, *dest;
+
+	buf = calloc(1, strlen(text) * 3); /* should be enough */
+	if (buf == NULL)
+		return ENOMEM;
+
+	dest = buf;
+	while (str < end) {
+		tuple = find_tuple(str);
+		if (tuple) {
+			sprintf(dest, "%s", tuple->to);
+			str += strlen(tuple->from);
+			dest += strlen(tuple->to);
+		} else if (strncmp(str, "{}", 2) == 0) {
+			str += 2;
+		} else {
+			sprintf(dest, "%c", *str);
+			str++;
+			dest++;
+		}
+	}
+
+	*out = buf;
+
+	return 0;
+}
diff --git a/harvard-kyoto.h b/harvard-kyoto.h
new file mode 100644
index 0000000..10727fb
--- /dev/null
+++ b/harvard-kyoto.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __HARVARD_KYOTO_H
+#define __HARVARD_KYOTO_H
+
+int encode_harvard_kyoto_to_iast(const char *text, char **out);
+
+#endif /* __HARVARD_KYOTO_H */
diff --git a/tests/harvard-kyoto.c b/tests/harvard-kyoto.c
new file mode 100644
index 0000000..caae9e3
--- /dev/null
+++ b/tests/harvard-kyoto.c
@@ -0,0 +1,30 @@
+#include "test.h"
+#include "harvard-kyoto.h"
+#include "../harvard-kyoto.h"
+
+static void test_harvard_kyoto(const char *hk, const char *iast)
+{
+	char *str;
+	int ret;
+
+	ret = encode_harvard_kyoto_to_iast(hk, &str);
+	ck_assert_int_eq(0, ret);
+	ck_assert_str_eq(iast, str);
+
+	free(str);
+}
+
+START_TEST(test_harvard_kyoto_encoding)
+{
+	test_harvard_kyoto("saMskRtam", "saṃskṛtam");
+	test_harvard_kyoto("yogaH", "yogaḥ");
+	test_harvard_kyoto("zaastraM shaastram", "śāstraṃ śāstram");
+	test_harvard_kyoto("liGga yajJa varNa", "liṅga yajña varṇa");
+	test_harvard_kyoto("Aaa Iii Uuu RR R L", "āā īī ūū ṝ ṛ ḷ");
+}
+END_TEST
+
+void register_harvard_kyoto_encoder_tests(TCase *test_case)
+{
+	tcase_add_test(test_case, test_harvard_kyoto_encoding);
+}
diff --git a/tests/harvard-kyoto.h b/tests/harvard-kyoto.h
new file mode 100644
index 0000000..c012724
--- /dev/null
+++ b/tests/harvard-kyoto.h
@@ -0,0 +1,8 @@
+#ifndef __TEST_HARVARD_KYOTO_H
+#define __TEST_HARVARD_KYOTO_H
+
+#include <check.h>
+
+void register_harvard_kyoto_encoder_tests(TCase *test_case);
+
+#endif /* __TEST_HARVARD_KYOTO_H */
diff --git a/tests/main.c b/tests/main.c
index cd94582..acd66a6 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -3,6 +3,7 @@
 #include "czech.h"
 #include "hindi.h"
 #include "velthuis.h"
+#include "harvard-kyoto.h"
 #include "utf8.h"
 #include "integration.h"
 
@@ -18,6 +19,7 @@ static Suite *create_test_suite()
 	register_transcript_czech_tests(test_case);
 	register_transcript_hindi_tests(test_case);
 	register_velthuis_encoder_tests(test_case);
+	register_harvard_kyoto_encoder_tests(test_case);
 	register_utf8_tests(test_case);
 
 	register_integration_tests(test_case);