CSS Properties

text-decoration

CSS property · 16 supported, 4 partial, 1 unsupported across 21 clients

16 of 21 email clients render text-decoration fully (Sep 2, 2026 data); it breaks outright in Proton Mail.

6/7 webmail, 4/6 desktop, 6/8 mobile clients support text-decoration fully.
Unsupported in Proton Mail.
Partial in Gmail Android, Gmail iOS, Outlook (New), Outlook Classic, behavior differs from browsers, test before relying on it.
Outlook Classic (Word engine, supported to at least 2029) does not fully support text-decoration, and its replacement changes little here; see the deprecation diff.
Across all clients, only 6 of 298 tracked HTML/CSS features render identically everywhere.

Source: caniemail.com (MIT), via the Emailens engine. Last tested upstream Feb 28, 2019, synced by Emailens Sep 2, 2026.

text-decoration controls underline, overline, and line-through styling and is critical for distinguishing links from body copy. Most email clients honor text-decoration on anchor tags, but client-side link styling sometimes adds an underline back even when you've set text-decoration: none.

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Supported
Gmail Android	mobile	Gmail Mobile	Partial^{See caveat 1}
Gmail iOS	mobile	Gmail Mobile	Partial^{See caveat 1}
Outlook 365	webmail	Outlook Web	Supported
Outlook (New)	desktop	Outlook Web	Partial^{See caveat 2}
Outlook Classic	desktop	Microsoft Word	Partial^{See caveat 2}
Outlook iOS	mobile	Outlook Mobile	Supported
Outlook Android	mobile	Outlook Mobile	Supported
Outlook for Mac	desktop	WebKit	Supported
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Supported
Yahoo Mail Android	mobile	Yahoo	Supported
Yahoo Mail iOS	mobile	Yahoo	Supported
Samsung Mail	mobile	Samsung	Supported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Supported
Proton Mail	webmail	Proton	Unsupported
AOL Mail	webmail	AOL	Supported
Fastmail	webmail	Fastmail	Supported
Superhuman	desktop	Blink	Supported

Documented caveats (2)

1.Gmail Android, Gmail iOS: Partial. Not supported with non Google accounts.
2.Outlook (New), Outlook Classic: Partial. Not supported with multiple values. Partial. overline is not supported.

Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.

Client-by-client behaviour for text-decoration

Fully supports text-decoration (16): Gmail, Outlook 365, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, AOL Mail, Fastmail, Superhuman.

Partial support (4): Gmail Android, Gmail iOS, Outlook (New), Outlook Classic. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

No support (1): Proton Mail. Plan fallbacks for these clients before relying on text-decoration in production sends.

When to use text-decoration in email

Removing underlines from CTA button anchors that are styled as buttons.
Strikethrough pricing in promotional emails (`text-decoration: line-through`).
Adding hover underline on web-mode email previews where pseudo-classes are honored.

Rendering behaviour and edge cases

Outlook on Windows applies a default underline to all <a> elements; you must declare text-decoration: none AND override the link color to fully un-style.
Apple Mail respects text-decoration but adds a phone-number / address link auto-underline that overrides yours , wrap such content in <a style="text-decoration:none;color:inherit"> to defeat it.
Yahoo Mail strips text-decoration from non-anchor elements in some sanitizer paths.

Recommended fallback strategy

When un-styling links, set text-decoration: none, color, and an explicit display: inline-block on the anchor for maximum coverage. For automatically-detected links (phones, addresses), wrap them yourself in styled anchor tags.