diff --git a/bin/pt-table-sync b/bin/pt-table-sync
index 33c4fab20..613e29a89 100755
--- a/bin/pt-table-sync
+++ b/bin/pt-table-sync
@@ -3612,6 +3612,14 @@ sub make_UPDATE {
       @cols = $self->sort_cols($row);
    }
    my $types = $self->{tbl_struct}->{type_for};
+
+   foreach my $col ( @cols ) {
+      my $is_json = ($types->{$col} || '') =~ m/json/i;
+      if ( $is_json && defined $row->{$col} && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col});
+      }
+   }
+
    return "UPDATE $self->{dst_db_tbl} SET "
       . join(', ', map {
             my $is_hex = ($types->{$_} || '') =~ m/^0x[0-9a-fA-F]+$/i;
@@ -3660,6 +3668,13 @@ sub make_row {
    my $q     = $self->{Quoter};
    my $type_for = $self->{tbl_struct}->{type_for};
 
+   foreach my $col ( @cols ) {
+      my $is_json = ($type_for->{$col} || '') =~ m/json/i;
+      if ( $is_json && defined $row->{$col} && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col});
+      }
+   }
+
    return "$verb INTO $self->{dst_db_tbl}("
       . join(', ', map { $q->quote($_) } @cols)
       . ') VALUES ('
diff --git a/lib/ChangeHandler.pm b/lib/ChangeHandler.pm
index c09c5148a..51b299187 100644
--- a/lib/ChangeHandler.pm
+++ b/lib/ChangeHandler.pm
@@ -324,6 +324,16 @@ sub make_UPDATE {
       @cols = $self->sort_cols($row);
    }
    my $types = $self->{tbl_struct}->{type_for};
+
+   # MySQL uses utf8mb4 for all strings in JSON, but
+   # DBD::mysql does not decode it accordingly
+   foreach my $col ( @cols ) {
+      my $is_json = ($types->{$col} || '') =~ m/json/i;
+      if ( $is_json && defined $row->{$col} && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col});
+      }
+   }
+
    return "UPDATE $self->{dst_db_tbl} SET "
       . join(', ', map {
             my $is_hex = ($types->{$_} || '') =~ m/^0x[0-9a-fA-F]+$/i;
@@ -403,6 +413,15 @@ sub make_row {
    my $q     = $self->{Quoter};
    my $type_for = $self->{tbl_struct}->{type_for};
 
+   # MySQL uses utf8mb4 for all strings in JSON, but
+   # DBD::mysql does not decode it accordingly
+   foreach my $col ( @cols ) {
+      my $is_json = ($type_for->{$col} || '') =~ m/json/i;
+      if ( $is_json && defined $row->{$col} && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col});
+      }
+   }
+
    return "$verb INTO $self->{dst_db_tbl}("
       . join(', ', map { $q->quote($_) } @cols)
       . ') VALUES ('
diff --git a/t/lib/ChangeHandler.t b/t/lib/ChangeHandler.t
index 311090794..5d7654cf4 100644
--- a/t/lib/ChangeHandler.t
+++ b/t/lib/ChangeHandler.t
@@ -7,6 +7,7 @@ BEGIN {
 };
 
 use strict;
+use utf8;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
 use Test::More;
@@ -538,6 +539,52 @@ SKIP: {
    );
 }
 
+# #############################################################################
+# PT-2377: pt-table-sync must handle utf8 in JSON columns correctly
+# #############################################################################
+SKIP: {
+   skip 'Cannot connect to sandbox master', 1 unless $master_dbh;
+   $master_dbh->do('DROP TABLE IF EXISTS `test`.`pt-2377`');
+   $master_dbh->do('CREATE TABLE `test`.`pt-2377` (id INT, data JSON)');
+   $master_dbh->do(q/INSERT INTO `test`.`pt-2377` VALUES (1, '{"name": "Müller"}')/);
+   $master_dbh->do(q/INSERT INTO `test`.`pt-2377` VALUES (2, NULL)/);
+
+   @rows = ();
+   $tbl_struct = {
+      cols      => [qw(id data)],
+      col_posn  => {id=>0, data=>1},
+      type_for  => {id=>'int', data=>'json'},
+   };
+   $ch = new ChangeHandler(
+      Quoter     => $q,
+      left_db    => 'test',
+      left_tbl   => 'pt-2377',
+      right_db   => 'test',
+      right_tbl  => 'pt-2377',
+      actions    => [ sub { push @rows, $_[0]; } ],
+      replace    => 0,
+      queue      => 0,
+      tbl_struct => $tbl_struct,
+   );
+   $ch->fetch_back($master_dbh);
+
+   $ch->change('UPDATE', {id=>1}, [qw(id)] );
+   $ch->change('INSERT', {id=>1}, [qw(id)] );
+   $ch->change('UPDATE', {id=>2}, [qw(id)] );
+   $ch->change('INSERT', {id=>2}, [qw(id)] );
+
+   is_deeply(
+      \@rows,
+      [
+         q/UPDATE `test`.`pt-2377` SET `data`='{"name": "Müller"}' WHERE `id`='1' LIMIT 1/,
+         q/INSERT INTO `test`.`pt-2377`(`id`, `data`) VALUES ('1', '{"name": "Müller"}')/,
+         q/UPDATE `test`.`pt-2377` SET `data`=NULL WHERE `id`='2' LIMIT 1/,
+         q/INSERT INTO `test`.`pt-2377`(`id`, `data`) VALUES ('2', NULL)/
+      ],
+      "UPDATE and INSERT quote data regardless of how it looks if tbl_struct->quote_val is true"
+   );
+}
+
 # #############################################################################
 # Done.
 # #############################################################################
diff --git a/t/pt-table-sync/pt-2377.t b/t/pt-table-sync/pt-2377.t
new file mode 100644
index 000000000..5f93ede39
--- /dev/null
+++ b/t/pt-table-sync/pt-2377.t
@@ -0,0 +1,80 @@
+#!/usr/bin/env perl
+
+BEGIN {
+   die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+      unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+   unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use Test::More;
+
+use PerconaTest;
+use Sandbox;
+require "$trunk/bin/pt-table-sync";
+
+my $dp = new DSNParser(opts=>$dsn_opts);
+my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $source_dbh = $sb->get_dbh_for('source');
+my $replica1_dbh = $sb->get_dbh_for('replica1');
+
+if ( !$source_dbh ) {
+   plan skip_all => 'Cannot connect to sandbox source';
+}
+elsif ( !$replica1_dbh ) {
+   plan skip_all => 'Cannot connect to sandbox replica1';
+}
+else {
+   plan tests => 3;
+}
+
+my $output;
+
+# #############################################################################
+# Test generated REPLACE statements.
+# #############################################################################
+$sb->load_file('source', "t/pt-table-sync/samples/pt-2377.sql");
+$sb->wait_for_replicas();
+$replica1_dbh->do("delete from `test`.`test_table` where `id`=1");
+
+$output = remove_traces(output(
+   sub { pt_table_sync::main('--sync-to-source',
+      'h=127.0.0.1,P=12346,u=msandbox,p=msandbox',
+      qw(-t test.test_table --print --execute))
+   },
+));
+chomp($output);
+is(
+   $output,
+   q/REPLACE INTO `test`.`test_table`(`id`, `data`) VALUES ('1', '{"name": "Müller"}');/,
+   "UTF8 characters of JSON values are printed correctly in REPLACE statements"
+);
+
+# #############################################################################
+# Test generated UPDATE statements.
+# #############################################################################
+$sb->load_file('source', "t/pt-table-sync/samples/pt-2377.sql");
+$sb->wait_for_replicas();
+$replica1_dbh->do(q/update `test`.`test_table` set `data`='{"reaction": "哈哈哈"}' where `id`=2/);
+
+$output = remove_traces(output(
+   sub { pt_table_sync::main(qw(--print --execute),
+      "h=127.0.0.1,P=12346,u=msandbox,p=msandbox,D=test,t=test_table",
+      "h=127.0.0.1,P=12345,u=msandbox,p=msandbox,D=test,t=test_table");
+   }
+));
+chomp($output);
+is(
+   $output,
+   q/UPDATE `test`.`test_table` SET `data`='{"reaction": "哈哈哈"}' WHERE `id`='2' LIMIT 1;/,
+   "UTF8 characters of JSON values are printed correctly in UPDATE statements"
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($source_dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+exit;
diff --git a/t/pt-table-sync/samples/pt-2377.sql b/t/pt-table-sync/samples/pt-2377.sql
new file mode 100644
index 000000000..084335118
--- /dev/null
+++ b/t/pt-table-sync/samples/pt-2377.sql
@@ -0,0 +1,14 @@
+DROP DATABASE IF EXISTS test;
+CREATE DATABASE test;
+USE test;
+
+CREATE TABLE `test_table` (
+  `id` INT AUTO_INCREMENT PRIMARY KEY,
+  `data` JSON NOT NULL
+) ENGINE=InnoDB;
+
+INSERT INTO
+  `test_table` (`data`)
+VALUES
+  ('{"name": "Müller"}'),
+  ('{"reaction": "哈哈"}');