diff --git a/modules/markup/html.go b/modules/markup/html.go
index 7961c5c930..aba287e0fd 100644
--- a/modules/markup/html.go
+++ b/modules/markup/html.go
@@ -1142,7 +1142,7 @@ func emojiShortCodeProcessor(ctx *RenderContext, node *html.Node) {
 		converted := emoji.FromAlias(alias)
 		if converted == nil {
 			// check if this is a custom reaction
-			if _, exist := setting.UI.CustomEmojisMap[alias]; exist {
+			if setting.UI.CustomEmojisLookup.Contains(alias) {
 				replaceContent(node, m[0], m[1], createCustomEmoji(alias))
 				node = node.NextSibling.NextSibling
 				start = 0
diff --git a/modules/markup/html_test.go b/modules/markup/html_test.go
index 6bc0f7e56c..22c7e4ca5d 100644
--- a/modules/markup/html_test.go
+++ b/modules/markup/html_test.go
@@ -358,7 +358,7 @@ func TestRender_emoji(t *testing.T) {
 	test(
 		":custom-emoji:",
 		`<p>:custom-emoji:</p>`)
-	setting.UI.CustomEmojisMap["custom-emoji"] = ":custom-emoji:"
+	setting.UI.CustomEmojisLookup.Add("custom-emoji")
 	test(
 		":custom-emoji:",
 		`<p><span class="emoji" aria-label="custom-emoji" data-alias="custom-emoji"><img alt=":custom-emoji:" src="`+setting.StaticURLPrefix+`/assets/img/emoji/custom-emoji.png"/></span></p>`)
diff --git a/modules/setting/ui.go b/modules/setting/ui.go
index 2e6a3df4c6..9dafe350eb 100644
--- a/modules/setting/ui.go
+++ b/modules/setting/ui.go
@@ -31,7 +31,7 @@ var UI = struct {
 	Reactions               []string
 	ReactionsLookup         container.Set[string] `ini:"-"`
 	CustomEmojis            []string
-	CustomEmojisMap         map[string]string `ini:"-"`
+	CustomEmojisLookup      container.Set[string] `ini:"-"`
 	SearchRepoDescription   bool
 	OnlyShowRelevantRepos   bool
 	ExploreDefaultSort      string `ini:"EXPLORE_PAGING_DEFAULT_SORT"`
@@ -87,7 +87,6 @@ var UI = struct {
 	Themes:                  []string{`forgejo-auto`, `forgejo-light`, `forgejo-dark`, `gitea-auto`, `gitea-light`, `gitea-dark`, `forgejo-auto-deuteranopia-protanopia`, `forgejo-light-deuteranopia-protanopia`, `forgejo-dark-deuteranopia-protanopia`, `forgejo-auto-tritanopia`, `forgejo-light-tritanopia`, `forgejo-dark-tritanopia`},
 	Reactions:               []string{`+1`, `-1`, `laugh`, `hooray`, `confused`, `heart`, `rocket`, `eyes`},
 	CustomEmojis:            []string{`git`, `gitea`, `codeberg`, `gitlab`, `github`, `gogs`, `forgejo`},
-	CustomEmojisMap:         map[string]string{"git": ":git:", "gitea": ":gitea:", "codeberg": ":codeberg:", "gitlab": ":gitlab:", "github": ":github:", "gogs": ":gogs:", "forgejo": ":forgejo:"},
 	ExploreDefaultSort:      "recentupdate",
 	PreferredTimestampTense: "mixed",
 
@@ -163,8 +162,6 @@ func loadUIFrom(rootCfg ConfigProvider) {
 	for _, reaction := range UI.Reactions {
 		UI.ReactionsLookup.Add(reaction)
 	}
-	UI.CustomEmojisMap = make(map[string]string)
-	for _, emoji := range UI.CustomEmojis {
-		UI.CustomEmojisMap[emoji] = ":" + emoji + ":"
-	}
+	UI.CustomEmojisLookup = make(container.Set[string])
+	UI.CustomEmojisLookup.AddMultiple(UI.CustomEmojis...)
 }
diff --git a/modules/templates/helper.go b/modules/templates/helper.go
index 42b4bad83c..8518290da0 100644
--- a/modules/templates/helper.go
+++ b/modules/templates/helper.go
@@ -128,8 +128,8 @@ func NewFuncMap() template.FuncMap {
 		"AllowedReactions": func() []string {
 			return setting.UI.Reactions
 		},
-		"CustomEmojis": func() map[string]string {
-			return setting.UI.CustomEmojisMap
+		"CustomEmojis": func() []string {
+			return setting.UI.CustomEmojis
 		},
 		"MetaAuthor": func() string {
 			return setting.UI.Meta.Author
diff --git a/templates/base/head_script.tmpl b/templates/base/head_script.tmpl
index d2774010b6..4bc274a73f 100644
--- a/templates/base/head_script.tmpl
+++ b/templates/base/head_script.tmpl
@@ -13,7 +13,7 @@ If you introduce mistakes in it, Gitea JavaScript code wouldn't run correctly.
 		assetVersionEncoded: encodeURIComponent('{{AssetVersion}}'), // will be used in URL construction directly
 		assetUrlPrefix: '{{AssetUrlPrefix}}',
 		runModeIsProd: {{.RunModeIsProd}},
-		customEmojis: {{CustomEmojis}},
+		customEmojis: new Set({{CustomEmojis}}),
 		csrfToken: '{{.CsrfToken}}',
 		pageData: {{.PageData}},
 		notificationSettings: {{NotificationSettings}}, {{/*a map provided by NewFuncMap in helper.go*/}}
diff --git a/web_src/js/features/emoji.js b/web_src/js/features/emoji.js
index 032a3efe8a..76555bfe05 100644
--- a/web_src/js/features/emoji.js
+++ b/web_src/js/features/emoji.js
@@ -2,7 +2,7 @@ import emojis from '../../../assets/emoji.json';
 
 const {assetUrlPrefix, customEmojis} = window.config;
 
-const tempMap = {...customEmojis};
+const tempMap = Object.assign(...Array.from(customEmojis, (v) => ({[v]: `:${v}:`})));
 for (const {emoji, aliases} of emojis) {
   for (const alias of aliases || []) {
     tempMap[alias] = emoji;
@@ -23,7 +23,7 @@ for (const key of emojiKeys) {
 // retrieve HTML for given emoji name
 export function emojiHTML(name) {
   let inner;
-  if (Object.hasOwn(customEmojis, name)) {
+  if (customEmojis.has(name)) {
     inner = `<img alt=":${name}:" src="${assetUrlPrefix}/img/emoji/${name}.png">`;
   } else {
     inner = emojiString(name);