diff --git a/CHANGELOG.md b/CHANGELOG.md
index e9e156182742..14de6a026592 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -105,6 +105,8 @@
 
 ### Fixes
 
+* `[jest-cli]` Fix stdin encoding to utf8 for watch plugins.
+  ([#6253](https://github.com/facebook/jest/issues/6253))
 * `[expect]` Better detection of DOM Nodes for equality
   ([#6246](https://github.com/facebook/jest/pull/6246))
 * `[jest-cli]` Fix misleading action description for F key when in "only failed
diff --git a/packages/jest-cli/src/__tests__/watch.test.js b/packages/jest-cli/src/__tests__/watch.test.js
index 736eb59e17c8..f214d70ab058 100644
--- a/packages/jest-cli/src/__tests__/watch.test.js
+++ b/packages/jest-cli/src/__tests__/watch.test.js
@@ -65,7 +65,7 @@ jest.doMock(
     class WatchPlugin1 {
       getUsageInfo() {
         return {
-          key: 's'.codePointAt(0),
+          key: 's',
           prompt: 'do nothing',
         };
       }
@@ -79,7 +79,7 @@ jest.doMock(
     class WatchPlugin2 {
       getUsageInfo() {
         return {
-          key: 'u'.codePointAt(0),
+          key: 'u',
           prompt: 'do something else',
         };
       }
@@ -90,7 +90,6 @@ jest.doMock(
 const watch = require('../watch').default;
 
 const nextTick = () => new Promise(res => process.nextTick(res));
-const toHex = char => Number(char.charCodeAt(0)).toString(16);
 
 afterEach(runJestMock.mockReset);
 
@@ -329,7 +328,7 @@ describe('Watch mode flows', () => {
           }
           getUsageInfo() {
             return {
-              key: 'p'.codePointAt(0),
+              key: 'p',
               prompt: 'custom "P" plugin',
             };
           }
@@ -352,7 +351,7 @@ describe('Watch mode flows', () => {
 
     expect(pipe.write.mock.calls.reverse()[0]).toMatchSnapshot();
 
-    stdin.emit(toHex('p'));
+    stdin.emit('p');
     await nextTick();
 
     expect(run).toHaveBeenCalled();
@@ -405,7 +404,7 @@ describe('Watch mode flows', () => {
           }
           getUsageInfo() {
             return {
-              key: 's'.codePointAt(0),
+              key: 's',
               prompt: 'do nothing',
             };
           }
@@ -424,7 +423,7 @@ describe('Watch mode flows', () => {
       stdin,
     );
 
-    stdin.emit(Number('s'.charCodeAt(0)).toString(16));
+    stdin.emit('s');
 
     await nextTick();
 
@@ -445,7 +444,7 @@ describe('Watch mode flows', () => {
           onKey() {}
           getUsageInfo() {
             return {
-              key: 's'.codePointAt(0),
+              key: 's',
               prompt: 'do nothing',
             };
           }
@@ -465,7 +464,7 @@ describe('Watch mode flows', () => {
           onKey() {}
           getUsageInfo() {
             return {
-              key: 'z'.codePointAt(0),
+              key: 'z',
               prompt: 'also do nothing',
             };
           }
@@ -484,14 +483,14 @@ describe('Watch mode flows', () => {
       stdin,
     );
 
-    stdin.emit(Number('s'.charCodeAt(0)).toString(16));
+    stdin.emit('s');
     await nextTick();
     expect(run).toHaveBeenCalled();
-    stdin.emit(Number('z'.charCodeAt(0)).toString(16));
+    stdin.emit('z');
     await nextTick();
     expect(showPrompt2).not.toHaveBeenCalled();
     await resolveShowPrompt();
-    stdin.emit(Number('z'.charCodeAt(0)).toString(16));
+    stdin.emit('z');
     expect(showPrompt2).toHaveBeenCalled();
   });
 
@@ -537,7 +536,7 @@ describe('Watch mode flows', () => {
     runJestMock.mockReset();
 
     stdin.emit(KEYS.T);
-    ['t', 'e', 's', 't'].map(toHex).forEach(key => stdin.emit(key));
+    ['t', 'e', 's', 't'].forEach(key => stdin.emit(key));
     stdin.emit(KEYS.ENTER);
     await nextTick();
 
@@ -556,7 +555,7 @@ describe('Watch mode flows', () => {
     runJestMock.mockReset();
 
     stdin.emit(KEYS.P);
-    ['f', 'i', 'l', 'e'].map(toHex).forEach(key => stdin.emit(key));
+    ['f', 'i', 'l', 'e'].forEach(key => stdin.emit(key));
     stdin.emit(KEYS.ENTER);
     await nextTick();
 
@@ -575,12 +574,12 @@ describe('Watch mode flows', () => {
     runJestMock.mockReset();
 
     stdin.emit(KEYS.P);
-    ['f', 'i', 'l', 'e'].map(toHex).forEach(key => stdin.emit(key));
+    ['f', 'i', 'l', 'e'].forEach(key => stdin.emit(key));
     stdin.emit(KEYS.ENTER);
     await nextTick();
 
     stdin.emit(KEYS.T);
-    ['t', 'e', 's', 't'].map(toHex).forEach(key => stdin.emit(key));
+    ['t', 'e', 's', 't'].forEach(key => stdin.emit(key));
     stdin.emit(KEYS.ENTER);
     await nextTick();
 
diff --git a/packages/jest-cli/src/__tests__/watch_filename_pattern_mode.test.js b/packages/jest-cli/src/__tests__/watch_filename_pattern_mode.test.js
index 2d3e8b7d281f..8201e6b72427 100644
--- a/packages/jest-cli/src/__tests__/watch_filename_pattern_mode.test.js
+++ b/packages/jest-cli/src/__tests__/watch_filename_pattern_mode.test.js
@@ -87,8 +87,6 @@ const watch = require('../watch').default;
 
 const nextTick = () => new Promise(res => process.nextTick(res));
 
-const toHex = char => Number(char.charCodeAt(0)).toString(16);
-
 const globalConfig = {watch: true};
 
 afterEach(runJestMock.mockReset);
@@ -122,11 +120,11 @@ describe('Watch mode flows', () => {
     };
 
     // Write a pattern
-    ['p', '.', '*', '1', '0'].map(toHex).forEach(assertPattern);
+    ['p', '.', '*', '1', '0'].forEach(assertPattern);
 
     [KEYS.BACKSPACE, KEYS.BACKSPACE].forEach(assertPattern);
 
-    ['3'].map(toHex).forEach(assertPattern);
+    ['3'].forEach(assertPattern);
 
     // Runs Jest again
     runJestMock.mockReset();
@@ -152,17 +150,14 @@ describe('Watch mode flows', () => {
     await nextTick();
 
     ['p', '.', '*', '1', '0']
-      .map(toHex)
+
       .concat(KEYS.ENTER)
       .forEach(key => stdin.emit(key));
 
     stdin.emit(KEYS.T);
     await nextTick();
 
-    ['t', 'e', 's', 't']
-      .map(toHex)
-      .concat(KEYS.ENTER)
-      .forEach(key => stdin.emit(key));
+    ['t', 'e', 's', 't'].concat(KEYS.ENTER).forEach(key => stdin.emit(key));
 
     await nextTick();
 
diff --git a/packages/jest-cli/src/__tests__/watch_test_name_pattern_mode.test.js b/packages/jest-cli/src/__tests__/watch_test_name_pattern_mode.test.js
index 3001f4cc37b1..376d89a4b4a0 100644
--- a/packages/jest-cli/src/__tests__/watch_test_name_pattern_mode.test.js
+++ b/packages/jest-cli/src/__tests__/watch_test_name_pattern_mode.test.js
@@ -99,8 +99,6 @@ jest.doMock('../lib/terminal_utils', () => ({
 
 const watch = require('../watch').default;
 
-const toHex = char => Number(char.charCodeAt(0)).toString(16);
-
 const globalConfig = {
   watch: true,
 };
@@ -136,11 +134,11 @@ describe('Watch mode flows', () => {
     };
 
     // Write a pattern
-    ['c', 'o', 'n', ' ', '1', '2'].map(toHex).forEach(assertPattern);
+    ['c', 'o', 'n', ' ', '1', '2'].forEach(assertPattern);
 
     [KEYS.BACKSPACE, KEYS.BACKSPACE].forEach(assertPattern);
 
-    ['*'].map(toHex).forEach(assertPattern);
+    ['*'].forEach(assertPattern);
 
     // Runs Jest again
     runJestMock.mockReset();
diff --git a/packages/jest-cli/src/constants.js b/packages/jest-cli/src/constants.js
index 0804d3922780..2ceae57dc2b2 100644
--- a/packages/jest-cli/src/constants.js
+++ b/packages/jest-cli/src/constants.js
@@ -12,28 +12,30 @@ const isWindows = process.platform === 'win32';
 export const CLEAR = isWindows ? '\x1B[2J\x1B[0f' : '\x1B[2J\x1B[3J\x1B[H';
 export const ARROW = ' \u203A ';
 export const KEYS = {
-  A: '61',
-  ARROW_DOWN: '1b5b42',
-  ARROW_LEFT: '1b5b44',
-  ARROW_RIGHT: '1b5b43',
-  ARROW_UP: '1b5b41',
-  BACKSPACE: isWindows ? '08' : '7f',
-  C: '63',
-  CONTROL_C: '03',
-  CONTROL_D: '04',
-  ENTER: '0d',
-  ESCAPE: '1b',
-  F: '66',
-  I: '69',
-  O: '6f',
-  P: '70',
-  Q: '71',
-  QUESTION_MARK: '3f',
-  R: '72',
-  S: '73',
-  T: '74',
-  U: '75',
-  W: '77',
+  A: 'a',
+  ARROW_DOWN: '\u001b[B',
+  ARROW_LEFT: '\u001b[D',
+  ARROW_RIGHT: '\u001b[C',
+  ARROW_UP: '\u001b[A',
+  BACKSPACE: isWindows
+    ? Buffer.from('08', 'hex').toString()
+    : Buffer.from('7f', 'hex').toString(),
+  C: 'c',
+  CONTROL_C: '\u0003',
+  CONTROL_D: '\u0004',
+  ENTER: '\r',
+  ESCAPE: '\u001b',
+  F: 'f',
+  I: 'i',
+  O: 'o',
+  P: 'p',
+  Q: 'q',
+  QUESTION_MARK: '?',
+  R: 'r',
+  S: 's',
+  T: 't',
+  U: 'u',
+  W: 'w',
 };
 
 export const ICONS = {
diff --git a/packages/jest-cli/src/lib/Prompt.js b/packages/jest-cli/src/lib/Prompt.js
index 402e0af2898b..cb49d3a1b585 100644
--- a/packages/jest-cli/src/lib/Prompt.js
+++ b/packages/jest-cli/src/lib/Prompt.js
@@ -84,12 +84,8 @@ export default class Prompt {
       case KEYS.ARROW_RIGHT:
         break;
       default:
-        const char = new Buffer(key, 'hex').toString();
-
         this._value =
-          key === KEYS.BACKSPACE
-            ? this._value.slice(0, -1)
-            : this._value + char;
+          key === KEYS.BACKSPACE ? this._value.slice(0, -1) : this._value + key;
         this._offset = -1;
         this._selection = null;
         this._onChange();
diff --git a/packages/jest-cli/src/lib/__tests__/prompt.test.js b/packages/jest-cli/src/lib/__tests__/prompt.test.js
index d3051921c0de..62c7a5cf9220 100644
--- a/packages/jest-cli/src/lib/__tests__/prompt.test.js
+++ b/packages/jest-cli/src/lib/__tests__/prompt.test.js
@@ -12,8 +12,8 @@ import Prompt from '../Prompt';
 import {KEYS} from '../../constants';
 
 const EXTRA_KEYS = Object.assign({}, KEYS, {
-  E: '65',
-  S: '73',
+  E: 'e',
+  S: 's',
 });
 
 it('calls handler on change value', () => {
diff --git a/packages/jest-cli/src/lib/handle_deprecation_warnings.js b/packages/jest-cli/src/lib/handle_deprecation_warnings.js
index a7ad7c612798..e07228b748af 100644
--- a/packages/jest-cli/src/lib/handle_deprecation_warnings.js
+++ b/packages/jest-cli/src/lib/handle_deprecation_warnings.js
@@ -28,7 +28,7 @@ export default (
       // $FlowFixMe
       stdin.setRawMode(true);
       stdin.resume();
-      stdin.setEncoding('hex');
+      stdin.setEncoding('utf8');
       stdin.on('data', (key: string) => {
         if (key === KEYS.ENTER) {
           resolve();
diff --git a/packages/jest-cli/src/lib/watch_plugins_helpers.js b/packages/jest-cli/src/lib/watch_plugins_helpers.js
index 08a7bc21f4b8..af05bc85248d 100644
--- a/packages/jest-cli/src/lib/watch_plugins_helpers.js
+++ b/packages/jest-cli/src/lib/watch_plugins_helpers.js
@@ -41,7 +41,7 @@ export const getSortedUsageRows = (
       const usageInfoB = b.getUsageInfo && b.getUsageInfo(globalConfig);
 
       if (usageInfoA && usageInfoB) {
-        return usageInfoA.key - usageInfoB.key;
+        return usageInfoA.key.localeCompare(usageInfoB.key);
       }
 
       return 0;
diff --git a/packages/jest-cli/src/plugins/quit.js b/packages/jest-cli/src/plugins/quit.js
index e9bcc781e7e5..dfcbf8db2f9a 100644
--- a/packages/jest-cli/src/plugins/quit.js
+++ b/packages/jest-cli/src/plugins/quit.js
@@ -29,7 +29,7 @@ class QuitPlugin extends BaseWatchPlugin {
 
   getUsageInfo() {
     return {
-      key: 'q'.codePointAt(0),
+      key: 'q',
       prompt: 'quit watch mode',
     };
   }
diff --git a/packages/jest-cli/src/plugins/test_name_pattern.js b/packages/jest-cli/src/plugins/test_name_pattern.js
index a293c5235d6c..4688ffa1ff58 100644
--- a/packages/jest-cli/src/plugins/test_name_pattern.js
+++ b/packages/jest-cli/src/plugins/test_name_pattern.js
@@ -27,7 +27,7 @@ class TestNamePatternPlugin extends BaseWatchPlugin {
 
   getUsageInfo() {
     return {
-      key: 't'.codePointAt(0),
+      key: 't',
       prompt: 'filter by a test name regex pattern',
     };
   }
diff --git a/packages/jest-cli/src/plugins/test_path_pattern.js b/packages/jest-cli/src/plugins/test_path_pattern.js
index 2dbb48dc1e31..3de06b7edf55 100644
--- a/packages/jest-cli/src/plugins/test_path_pattern.js
+++ b/packages/jest-cli/src/plugins/test_path_pattern.js
@@ -28,7 +28,7 @@ class TestPathPatternPlugin extends BaseWatchPlugin {
 
   getUsageInfo() {
     return {
-      key: 'p'.codePointAt(0),
+      key: 'p',
       prompt: 'filter by a filename regex pattern',
     };
   }
diff --git a/packages/jest-cli/src/plugins/update_snapshots.js b/packages/jest-cli/src/plugins/update_snapshots.js
index f405c1c54ede..8f8d0a40425a 100644
--- a/packages/jest-cli/src/plugins/update_snapshots.js
+++ b/packages/jest-cli/src/plugins/update_snapshots.js
@@ -39,7 +39,7 @@ class UpdateSnapshotsPlugin extends BaseWatchPlugin {
   getUsageInfo(globalConfig: GlobalConfig) {
     if (this._hasSnapshotFailure) {
       return {
-        key: 'u'.codePointAt(0),
+        key: 'u',
         prompt: 'update failing snapshots',
       };
     }
diff --git a/packages/jest-cli/src/plugins/update_snapshots_interactive.js b/packages/jest-cli/src/plugins/update_snapshots_interactive.js
index 75c1c020cf15..c05da8a97465 100644
--- a/packages/jest-cli/src/plugins/update_snapshots_interactive.js
+++ b/packages/jest-cli/src/plugins/update_snapshots_interactive.js
@@ -99,7 +99,7 @@ class UpdateSnapshotInteractivePlugin extends BaseWatchPlugin {
       this._failedSnapshotTestAssertions.length > 0
     ) {
       return {
-        key: 'i'.codePointAt(0),
+        key: 'i',
         prompt: 'update failing snapshots interactively',
       };
     }
diff --git a/packages/jest-cli/src/types.js b/packages/jest-cli/src/types.js
index 51ec43e5da94..664065b6c083 100644
--- a/packages/jest-cli/src/types.js
+++ b/packages/jest-cli/src/types.js
@@ -10,7 +10,7 @@ import type {GlobalConfig} from 'types/Config';
 import type {JestHookSubscriber} from './jest_hooks';
 
 export type UsageData = {
-  key: number,
+  key: string,
   prompt: string,
 };
 
diff --git a/packages/jest-cli/src/watch.js b/packages/jest-cli/src/watch.js
index 89f9ad058965..4279625deaf1 100644
--- a/packages/jest-cli/src/watch.js
+++ b/packages/jest-cli/src/watch.js
@@ -277,7 +277,7 @@ export default function watch(
     ).find(plugin => {
       const usageData =
         (plugin.getUsageInfo && plugin.getUsageInfo(globalConfig)) || {};
-      return usageData.key === parseInt(key, 16);
+      return usageData.key === key;
     });
 
     if (matchingWatchPlugin != null) {
@@ -359,7 +359,7 @@ export default function watch(
   if (typeof stdin.setRawMode === 'function') {
     stdin.setRawMode(true);
     stdin.resume();
-    stdin.setEncoding('hex');
+    stdin.setEncoding('utf8');
     stdin.on('data', onKeypress);
   }
 
@@ -405,7 +405,7 @@ const usage = (
       plugin =>
         chalk.dim(' \u203A Press') +
         ' ' +
-        String.fromCodePoint(plugin.key) +
+        plugin.key +
         ' ' +
         chalk.dim(`to ${plugin.prompt}.`),
     ),