diff --git a/web/chat/mention-suggestion-tooltip.css b/web/chat/mention-suggestion-tooltip.css
new file mode 100644
index 000000000..3e1a515ad
--- /dev/null
+++ b/web/chat/mention-suggestion-tooltip.css
@@ -0,0 +1,58 @@
+.suggestionsContainer {
+  position: fixed;
+  box-sizing: border-box;
+
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+
+  width: 296px;
+  max-height: 268px;
+  padding: 8px;
+
+  background: var(--typeahead-overlay-dark);
+
+  border: 1px solid var(--typeahead-overlay-light);
+  box-shadow: 0px 1px 2px var(--typeahead-overlay-shadow-primary),
+    0px 4px 12px var(--typeahead-overlay-shadow-secondary);
+  border-radius: 8px;
+
+  overflow-y: scroll;
+  overflow-x: hidden;
+}
+
+.suggestion {
+  box-sizing: border-box;
+
+  display: flex;
+  flex-direction: row;
+  align-items: center;
+  justify-content: left;
+  padding: 8px;
+
+  width: 280px;
+  height: 40px;
+
+  background: var(--typeahead-overlay-dark);
+  border: 0;
+  border-radius: 4px;
+
+  color: var(--typeahead-overlay-text);
+
+  font-family: var(--font-stack);
+  font-size: var(--m-font-16);
+  font-weight: var(--normal);
+
+  line-height: var(--line-height-text);
+}
+
+.suggestion span {
+  display: inline-block;
+  text-overflow: ellipsis;
+  overflow: hidden;
+  white-space: nowrap;
+}
+
+.suggestion:hover {
+  background-color: var(--typeahead-overlay-light);
+}
diff --git a/web/chat/mention-suggestion-tooltip.react.js b/web/chat/mention-suggestion-tooltip.react.js
new file mode 100644
index 000000000..243e001b7
--- /dev/null
+++ b/web/chat/mention-suggestion-tooltip.react.js
@@ -0,0 +1,55 @@
+// @flow
+
+import * as React from 'react';
+
+import Button from '../components/button.react';
+import css from './mention-suggestion-tooltip.css';
+
+export type MentionSuggestionTooltipAction = {
+  +key: string,
+  +onClick: (SyntheticEvent<HTMLButtonElement>) => mixed,
+  +actionButtonContent: React.Node,
+};
+
+export type TooltipPosition = {
+  +top: number,
+  +left: number,
+};
+export type MentionSuggestionTooltipProps = {
+  +actions: $ReadOnlyArray<MentionSuggestionTooltipAction>,
+  +tooltipPosition: TooltipPosition,
+};
+
+function MentionSuggestionTooltip(
+  props: MentionSuggestionTooltipProps,
+): React.Node {
+  const { actions, tooltipPosition } = props;
+
+  const tooltipPositionStyle = React.useMemo(
+    () => ({
+      top: tooltipPosition.top,
+      left: tooltipPosition.left,
+    }),
+    [tooltipPosition],
+  );
+
+  const tooltipButtons = React.useMemo(() => {
+    return actions.map(({ key, onClick, actionButtonContent }) => (
+      <Button key={key} onClick={onClick} className={css.suggestion}>
+        <span>@{actionButtonContent}</span>
+      </Button>
+    ));
+  }, [actions]);
+
+  if (!actions || actions.length === 0) {
+    return null;
+  }
+
+  return (
+    <div className={css.suggestionsContainer} style={tooltipPositionStyle}>
+      {tooltipButtons}
+    </div>
+  );
+}
+
+export default MentionSuggestionTooltip;
diff --git a/web/theme.css b/web/theme.css
index 076fdb82f..76a62c5ca 100644
--- a/web/theme.css
+++ b/web/theme.css
@@ -1,188 +1,193 @@
 :root {
   /* Never use color values defined here directly in CSS. Add color variables to "Color Theme" below
 
      The reason we never use color values defined here directly in CSS is
 
       1. It makes changing themes from light / dark / user generated impossible.
       2. Gives the programmer context into the color being used.
       3. If our color system changes it's much easier to change color values in one place.
 
      Add a color value to the theme below, and then use it in your CSS.
      naming convention:
      - bg: background.
      - fg: foreground.
      - color: text-color
    */
   --shades-white-100: #ffffff;
   --shades-white-90: #f5f5f5;
   --shades-white-80: #ebebeb;
   --shades-white-70: #e0e0e0;
   --shades-white-60: #cccccc;
 
   --shades-black-100: #0a0a0a;
   --shades-black-90: #1f1f1f;
   --shades-black-80: #404040;
   --shades-black-70: #666666;
   --shades-black-60: #808080;
 
   --violet-dark-100: #7e57c2;
   --violet-dark-80: #6d49ab;
   --violet-dark-60: #563894;
   --violet-dark-40: #44297a;
   --violet-dark-20: #331f5c;
 
   --violet-light-100: #ae94db;
   --violet-light-80: #b9a4df;
   --violet-light-60: #d3c6ec;
   --violet-light-40: #e8e0f5;
   --violet-light-20: #f3f0fa;
 
   --success-light-10: #d5f6e3;
   --success-light-50: #6cdf9c;
   --success-primary: #00c853;
   --success-dark-50: #029841;
   --success-dark-90: #034920;
 
   --error-light-10: #feebe6;
   --error-light-50: #f9947b;
   --error-primary: #f53100;
   --error-dark-50: #b62602;
   --error-dark-90: #4f1203;
 
   --logo-bg: #111827;
 
   --bg: var(--shades-black-100);
   --fg: var(--shades-white-100);
   --color-disabled: var(--shades-black-60);
   --text-input-bg: var(--shades-black-80);
   --text-input-color: var(--shades-white-60);
   --text-input-placeholder: var(--shades-white-60);
   --border: var(--shades-black-80);
   --error: var(--error-primary);
   --success: var(--success-dark-50);
 
   /* Color Theme */
   --btn-bg-filled: var(--violet-dark-100);
   --btn-bg-outline: var(--shades-black-90);
   --btn-bg-success: var(--success-dark-50);
   --btn-bg-danger: var(--error-primary);
   --btn-bg-disabled: var(--shades-black-80);
   --btn-disabled-color: var(--shades-black-60);
   --chat-bg: var(--violet-dark-80);
   --chat-confirmation-icon: var(--violet-dark-100);
   --keyserver-selection: var(--violet-dark-60);
   --thread-selection: var(--violet-light-80);
   --thread-hover-bg: var(--shades-black-80);
   --thread-active-bg: var(--shades-black-80);
   --chat-timestamp-color: var(--shades-black-60);
   --tool-tip-bg: var(--shades-black-80);
   --tool-tip-color: var(--shades-white-60);
   --border-color: var(--shades-black-80);
   --calendar-chevron: var(--shades-black-60);
   --calendar-day-bg: var(--shades-black-60);
   --calendar-day-selected-color: var(--violet-dark-80);
   --community-bg: var(--shades-black-90);
   --community-settings-selected: var(--violet-dark-60);
   --unread-bg: var(--error-primary);
   --settings-btn-bg: var(--violet-dark-100);
   --modal-bg: var(--shades-black-90);
   --modal-fg: var(--shades-white-60);
   --join-bg: var(--shades-black-90);
   --help-color: var(--shades-black-60);
   --breadcrumb-color: var(--shades-white-60);
   --breadcrumb-color-unread: var(--shades-white-60);
   --btn-outline-border: var(--shades-black-60);
   --thread-color-read: var(--shades-black-60);
   --thread-from-color-read: var(--shades-black-80);
   --thread-last-message-color-read: var(--shades-black-60);
   --relationship-button-green: var(--success-dark-50);
   --relationship-button-red: var(--error-primary);
   --relationship-button-text: var(--fg);
   --disconnected-bar-alert-bg: var(--error-dark-50);
   --disconnected-bar-alert-color: var(--shades-white-100);
   --disconnected-bar-connecting-bg: var(--shades-white-70);
   --disconnected-bar-connecting-color: var(--shades-black-100);
   --permission-color: var(--shades-white-60);
   --thread-top-bar-color: var(--shades-white-100);
   --thread-top-bar-menu-color: var(--shades-white-70);
   --thread-ancestor-keyserver-border: var(--shades-black-70);
   --thread-ancestor-color-light: var(--shades-white-70);
   --thread-ancestor-color-dark: var(--shades-black-100);
   --thread-ancestor-separator-color: var(--shades-white-60);
   --text-message-default-background: var(--shades-black-80);
   --message-action-tooltip-bg: var(--shades-black-90);
   --menu-bg: var(--shades-black-90);
   --menu-bg-light: var(--shades-black-80);
   --menu-separator-color: var(--shades-black-80);
   --menu-color: var(--shades-black-60);
   --menu-color-light: var(--shades-white-60);
   --menu-color-hover: var(--shades-white-100);
   --menu-color-dangerous: var(--error-primary);
   --menu-color-dangerous-hover: var(--error-light-50);
   --app-list-icon-read-only-color: var(--shades-black-60);
   --app-list-icon-enabled-color: var(--success-primary);
   --app-list-icon-disabled-color: var(--shades-white-80);
   --account-settings-label: var(--shades-black-60);
   --account-button-color: var(--violet-dark-100);
   --chat-thread-list-color-active: var(--shades-white-60);
   --chat-thread-list-menu-color: var(--shades-white-60);
   --chat-thread-list-menu-bg: var(--shades-black-80);
   --chat-thread-list-menu-active-color: var(--shades-white-60);
   --chat-thread-list-menu-active-bg: var(--shades-black-90);
   --search-clear-color: var(--shades-white-100);
   --search-clear-bg: var(--shades-black-70);
   --search-input-color: var(--shades-white-100);
   --search-input-placeholder: var(--shades-black-60);
   --search-icon-color: var(--shades-black-60);
   --tabs-header-active-color: var(--shades-white-100);
   --tabs-header-active-border: var(--violet-light-100);
   --tabs-header-background-color: var(--shades-black-60);
   --tabs-header-background-border: var(--shades-black-80);
   --tabs-header-background-color-hover: var(--shades-white-80);
   --tabs-header-background-border-hover: var(--shades-black-70);
   --members-modal-member-text: var(--shades-black-60);
   --members-modal-member-text-hover: var(--shades-white-100);
   --label-default-bg: var(--violet-dark-80);
   --label-default-color: var(--shades-white-80);
   --subchannels-modal-color: var(--shades-black-60);
   --subchannels-modal-color-hover: var(--shades-white-100);
   --color-selector-active-bg: var(--shades-black-80);
   --relationship-modal-color: var(--shades-black-60);
   --arrow-extension-color: var(--shades-black-60);
   --modal-close-color: var(--shades-black-60);
   --modal-close-color-hover: var(--shades-white-100);
   --add-members-group-header-color: var(--shades-black-60);
   --add-members-item-color: var(--shades-black-60);
   --add-members-item-color-hover: var(--shades-white-100);
   --add-members-item-disabled-color: var(--shades-black-80);
   --add-members-item-disabled-color-hover: var(--shades-black-60);
   --add-members-remove-pending-color: var(--error-primary);
   --add-members-remove-pending-color-hover: var(--error-light-50);
   --radio-border: var(--shades-black-70);
   --radio-color: var(--shades-white-60);
   --notification-settings-option-selected-bg: var(--shades-black-80);
   --notification-settings-option-title-color: var(--shades-white-90);
   --notification-settings-option-color: var(--shades-white-60);
   --notification-settings-option-invalid-color: var(--shades-black-80);
   --notification-settings-option-invalid-selected-color: var(--shades-black-60);
   --danger-zone-subheading-color: var(--shades-white-60);
   --danger-zone-explanation-color: var(--shades-black-60);
   --thread-creation-search-container-bg: var(--shades-black-90);
   --thread-creation-close-search-color: var(--shades-black-60);
   --thread-creation-search-item-bg-hover: var(--shades-black-80);
   --thread-creation-search-item-info-color: var(--shades-black-60);
   --chat-message-list-active-border: #5989d6;
   --sidebars-modal-color: var(--shades-black-60);
   --sidebars-modal-color-hover: var(--shades-white-100);
   --inline-sidebar-bg: var(--shades-black-70);
   --inline-sidebar-bg-hover: var(--shades-black-80);
   --inline-sidebar-color: var(--fg);
   --compose-subchannel-header-fg: var(--shades-black-60);
   --compose-subchannel-header-bg: var(--shades-black-80);
   --compose-subchannel-label-color: var(--shades-black-60);
   --compose-subchannel-mark-color: var(--violet-light-100);
   --enum-option-icon-color: var(--violet-dark-100);
   --show-password-bg-hover: var(--shades-black-70);
+  --typeahead-overlay-light: var(--shades-black-80);
+  --typeahead-overlay-dark: var(--shades-black-90);
+  --typeahead-overlay-text: var(--shades-white-100);
+  --typeahead-overlay-shadow-primary: rgba(0, 0, 0, 0.25);
+  --typeahead-overlay-shadow-secondary: rgba(0, 0, 0, 0.4);
   --spoiler-text-color: var(--shades-black-80);
   --spoiler-background-color: var(--shades-black-80);
 }