diff --git a/options/locale_next/locale_en-US.json b/options/locale_next/locale_en-US.json
index c7e9f65a68..356aaaead0 100644
--- a/options/locale_next/locale_en-US.json
+++ b/options/locale_next/locale_en-US.json
@@ -94,5 +94,6 @@
     "editor.textarea.shift_tab_hint": "No indentation on this line. Press <kbd>Shift</kbd> + <kbd>Tab</kbd> again or <kbd>Escape</kbd> to leave the editor.",
     "admin.dashboard.cleanup_offline_runners": "Cleanup offline runners",
     "settings.visibility.description": "Profile visibility affects others' ability to access your non-private repositories. <a href=\"%s\" target=\"_blank\">Learn more</a>",
+    "avatar.constraints_hint": "Custom avatar may not exceed %[1]s in size or be larger than %[2]dx%[3]d pixels",
     "meta.last_line": "Thank you for translating Forgejo! This line isn't seen by the users but it serves other purposes in the translation management. You can place a fun fact in the translation instead of translating it."
 }
diff --git a/routers/web/admin/users.go b/routers/web/admin/users.go
index 0188df17b4..964326291e 100644
--- a/routers/web/admin/users.go
+++ b/routers/web/admin/users.go
@@ -313,6 +313,9 @@ func editUserCommon(ctx *context.Context) {
 	ctx.Data["DisableMigrations"] = setting.Repository.DisableMigrations
 	ctx.Data["AllowedUserVisibilityModes"] = setting.Service.AllowedUserVisibilityModesSlice.ToVisibleTypeSlice()
 	ctx.Data["DisableGravatar"] = setting.Config().Picture.DisableGravatar.Value(ctx)
+	ctx.Data["MaxAvatarFileSize"] = setting.Avatar.MaxFileSize
+	ctx.Data["MaxAvatarWidth"] = setting.Avatar.MaxWidth
+	ctx.Data["MaxAvatarHeight"] = setting.Avatar.MaxHeight
 }
 
 // EditUser show editing user page
diff --git a/routers/web/org/setting.go b/routers/web/org/setting.go
index 284f406413..c83242754b 100644
--- a/routers/web/org/setting.go
+++ b/routers/web/org/setting.go
@@ -50,6 +50,9 @@ func Settings(ctx *context.Context) {
 	ctx.Data["RepoAdminChangeTeamAccess"] = ctx.Org.Organization.RepoAdminChangeTeamAccess
 	ctx.Data["ContextUser"] = ctx.ContextUser
 	ctx.Data["CooldownPeriod"] = setting.Service.UsernameCooldownPeriod
+	ctx.Data["MaxAvatarFileSize"] = setting.Avatar.MaxFileSize
+	ctx.Data["MaxAvatarWidth"] = setting.Avatar.MaxWidth
+	ctx.Data["MaxAvatarHeight"] = setting.Avatar.MaxHeight
 
 	err := shared_user.LoadHeaderCount(ctx)
 	if err != nil {
diff --git a/routers/web/repo/setting/setting.go b/routers/web/repo/setting/setting.go
index c59225ba49..b65d1fbc92 100644
--- a/routers/web/repo/setting/setting.go
+++ b/routers/web/repo/setting/setting.go
@@ -64,6 +64,9 @@ func SettingsCtxData(ctx *context.Context) {
 	ctx.Data["DisableNewPushMirrors"] = setting.Mirror.DisableNewPush
 	ctx.Data["DefaultMirrorInterval"] = setting.Mirror.DefaultInterval
 	ctx.Data["MinimumMirrorInterval"] = setting.Mirror.MinInterval
+	ctx.Data["MaxAvatarFileSize"] = setting.Avatar.MaxFileSize
+	ctx.Data["MaxAvatarWidth"] = setting.Avatar.MaxWidth
+	ctx.Data["MaxAvatarHeight"] = setting.Avatar.MaxHeight
 
 	signing, _ := asymkey_service.SigningKey(ctx, ctx.Repo.Repository.RepoPath())
 	ctx.Data["SigningKeyAvailable"] = len(signing) > 0
diff --git a/routers/web/user/setting/profile.go b/routers/web/user/setting/profile.go
index fe6ffb802d..0ddb1b21f5 100644
--- a/routers/web/user/setting/profile.go
+++ b/routers/web/user/setting/profile.go
@@ -51,6 +51,9 @@ func Profile(ctx *context.Context) {
 	ctx.Data["DisableGravatar"] = setting.Config().Picture.DisableGravatar.Value(ctx)
 	ctx.Data["CooldownPeriod"] = setting.Service.UsernameCooldownPeriod
 	ctx.Data["CommonPronouns"] = commonPronouns
+	ctx.Data["MaxAvatarFileSize"] = setting.Avatar.MaxFileSize
+	ctx.Data["MaxAvatarWidth"] = setting.Avatar.MaxWidth
+	ctx.Data["MaxAvatarHeight"] = setting.Avatar.MaxHeight
 
 	ctx.HTML(http.StatusOK, tplSettingsProfile)
 }
diff --git a/templates/admin/user/edit.tmpl b/templates/admin/user/edit.tmpl
index 7d004dd903..a1ff3d4117 100644
--- a/templates/admin/user/edit.tmpl
+++ b/templates/admin/user/edit.tmpl
@@ -208,6 +208,7 @@
 				<div class="inline field tw-pl-4">
 					<label for="avatar">{{ctx.Locale.Tr "settings.choose_new_avatar"}}</label>
 					<input name="avatar" type="file" accept="image/png,image/jpeg,image/gif,image/webp">
+					<br/><span class=help>{{ctx.Locale.Tr "avatar.constraints_hint" (ctx.Locale.TrSize .MaxAvatarFileSize) .MaxAvatarWidth .MaxAvatarHeight}}</span>
 				</div>
 
 				<div class="field">
diff --git a/templates/org/settings/options.tmpl b/templates/org/settings/options.tmpl
index 2ef7031aef..562f3f3ae3 100644
--- a/templates/org/settings/options.tmpl
+++ b/templates/org/settings/options.tmpl
@@ -94,6 +94,7 @@
 						<div class="inline field">
 							<label for="avatar">{{ctx.Locale.Tr "settings.choose_new_avatar"}}</label>
 							<input name="avatar" type="file" accept="image/png,image/jpeg,image/gif,image/webp">
+							<br/><span class=help>{{ctx.Locale.Tr "avatar.constraints_hint" (ctx.Locale.TrSize .MaxAvatarFileSize) .MaxAvatarWidth .MaxAvatarHeight}}</span>
 						</div>
 
 						<div class="field">
diff --git a/templates/repo/settings/options.tmpl b/templates/repo/settings/options.tmpl
index a6f30c27ed..797dbe403b 100644
--- a/templates/repo/settings/options.tmpl
+++ b/templates/repo/settings/options.tmpl
@@ -56,6 +56,7 @@
 				<div class="inline field">
 					<label for="avatar">{{ctx.Locale.Tr "settings.choose_new_avatar"}}</label>
 					<input name="avatar" type="file" accept="image/png,image/jpeg,image/gif,image/webp">
+					<br/><span class=help>{{ctx.Locale.Tr "avatar.constraints_hint" (ctx.Locale.TrSize .MaxAvatarFileSize) .MaxAvatarWidth .MaxAvatarHeight}}</span>
 				</div>
 				<div class="field">
 					<button class="ui primary button">{{ctx.Locale.Tr "settings.update_avatar"}}</button>
diff --git a/templates/user/settings/profile.tmpl b/templates/user/settings/profile.tmpl
index e4c3e82727..203da3f341 100644
--- a/templates/user/settings/profile.tmpl
+++ b/templates/user/settings/profile.tmpl
@@ -138,6 +138,7 @@
 				<div class="inline field tw-pl-4">
 					<label for="new-avatar">{{ctx.Locale.Tr "settings.choose_new_avatar"}}</label>
 					<input id="new-avatar" name="avatar" type="file" accept="image/png,image/jpeg,image/gif,image/webp">
+					<br/><span class=help>{{ctx.Locale.Tr "avatar.constraints_hint" (ctx.Locale.TrSize .MaxAvatarFileSize) .MaxAvatarWidth .MaxAvatarHeight}}</span>
 				</div>
 
 				<div class="field">
diff --git a/tests/integration/setting_test.go b/tests/integration/setting_test.go
index 409ef5132a..0456d5cfff 100644
--- a/tests/integration/setting_test.go
+++ b/tests/integration/setting_test.go
@@ -155,3 +155,51 @@ func TestSettingSecurityAuthSource(t *testing.T) {
 	assert.Contains(t, resp.Body.String(), `gitlab-active`)
 	assert.Contains(t, resp.Body.String(), `gitlab-inactive`)
 }
+
+func TestUserAvatarSizeNotice(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user1")
+	req := NewRequest(t, "GET", "/user/settings")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	assert.Contains(t,
+		htmlDoc.doc.Find("form div:has(input#new-avatar) .help").Text(),
+		"Custom avatar may not exceed 1 MiB in size or be larger than 4096x4096 pixels")
+}
+
+func TestRepoAvatarSizeNotice(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user2")
+	req := NewRequest(t, "GET", "/user2/repo1/settings")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	assert.Contains(t,
+		htmlDoc.doc.Find("form div:has(input[name=\"avatar\"]) .help").Text(),
+		"Custom avatar may not exceed 1 MiB in size or be larger than 4096x4096 pixels")
+}
+
+func TestOrgAvatarSizeNotice(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user2")
+	req := NewRequest(t, "GET", "/org/org3/settings")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	assert.Contains(t,
+		htmlDoc.doc.Find("form div:has(input[name=\"avatar\"]) .help").Text(),
+		"Custom avatar may not exceed 1 MiB in size or be larger than 4096x4096 pixels")
+}
+
+func TestAdminAvatarSizeNotice(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user1")
+	req := NewRequest(t, "GET", "/admin/users/2/edit")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	assert.Contains(t,
+		htmlDoc.doc.Find("form div:has(input[name=\"avatar\"]) .help").Text(),
+		"Custom avatar may not exceed 1 MiB in size or be larger than 4096x4096 pixels")
+}