Stable AMO Version, see changelog for details.

Supported browsers: Firefox (Desktop and Mobile on Android), SeaMonkey, Tor Browser (where it is built-in).
Other browsers based on Gecko versions >= 45 might work, but are not tested.

Direct download

You can get latest stable version here, too, using this direct download link for NoScript 10.1.7.5
To install, just drag and drop it onto your address bar.

v 10.1.7.5
=============================================================
x Fixed edge case CSP injection bug (thanks Rob Wu)
x Optimized dynamic script injection (thanks Rob Wu)
x Fixed potential leak on dynamic script injection (thanks
  Rob Wu for report)
x Now NoScript's UI on privileged pages explains permissions
  cannot be configured there, rather than bluntly opening the
  Options page (thanks Rob Wu for suggestion)

v 10.1.7.4
=============================================================
x Fixed script enablement status not correctly detected on
  some pages rolling their own CSP (causing NOSCRIPT element
  and META refresh emulation not to be triggered)
x Fixed "Appearance" NoScript Options tab missing on Android
x [XSS] Fixed semicolon-separated JSON payloads DDOSing the
  JSON-optimizer, e.g. with syndication.twitter.com subframes
  (thanks KonomiKitten and pal1000 for reports)
x [UI] Renamed "Scripts globally allowed (dangerous)" option
  to "No permissions enforcement (dangerous)" to better
  reflect its actual effect
x [UI] Better feedback about "No permission enforcement" by
  disabling the "Preset customization" section and and the
  "Per-site Permissions" tab
x [UI] Moved XSS-related options to the "Advanced" tab
x Fixed disabled webgl breaking feeds on script-enabled sites
  (thanks pal1000 for reporting)
x Enhanced dynamic script injection if browser.contentScripts
  API is available
x Expanded support for webgl canvas placeholders

If you find any problem installing it, this FAQ may help.

You can still download NoScript "Classic" (5.1.8.5) for Firefox 52 ESR here: it will be updated until June 2018, when ESR and the Tor Browser based on it will switch to 59.

v 5.1.8.5
=============================================================
x Switched to unified update URL for Quantum beta and Classic
x Automatic updates test
+ Updates for NoScript Classic are now served directly from
  secure.informaction.com due to beta channel deprecation and
  other problems with dual branches on AMO
x Fixed edge case ABE Anon action loop with e10s enabled on
  reload after new rule (thanks barbaz for reporting)
x Fixed JSON interactive view disabled by cascading
  restrictions (thanks jester for reporting)
x Fixed ABE Anon action loop with e10s enabled (thanks barbaz
  for reporting)

Users of Firefox 44 and below are urged to upgrade their very unsafe browser. For those few who can't,

• latest NoScript version compatible with Gecko 46 - Gecko 56 is 5.1.x;
• latest NoScript version compatible with Gecko 13 - Gecko 45 is 2.9.0.14;
• latest NoScript version compatible with Gecko 1.9 - Gecko 12 is 2.9.0.1rc1;
• latest NoScript version compatible with Gecko < 1.9 is 1.10.

Development version

If you're brave enough and you need a specific feature or fix not released yet, or you simply want to provide feedback before official release, you may want try this
"Quantum" NoScript 10.1.8.1rc2 development build (here the "Classic" NoScript 5.1.8.5rc3 development build).

Recent development history:

v 10.1.8.1rc2
=============================================================
x [UI] Improved in-popup messages
x [UI] More consistent interactions between the bulk
  restrictions disablement features

v 10.1.8.1rc1
=============================================================
+ [UI] "Disable restrictions for this tab" button in popup
+ [UI] "Disable restrictions globally" button in popup
x [UI] Simplified URL management in "Allow object" prompt
x Fixed dynamic scripts URL matching inconsistencies

v 5.1.8.5rc3
=============================================================
x Switched to unified update URL for Quantum beta and Classic
x Automatic updates test

v 5.1.8.5rc2
=============================================================
+ Updates for NoScript Classic are now served directly from
  secure.informaction.com due to beta channel deprecation and
  other problems with dual branches on AMO
x Fixed edge case ABE Anon action loop with e10s enabled on
  reload after new rule (thanks barbaz for reporting)

v 5.1.8.5rc1
=============================================================
x Fixed JSON interactive view disabled by cascading
  restrictions (thanks jester for reporting)
x Fixed ABE Anon action loop with e10s enabled (thanks barbaz
  for reporting)

Feedback

If you find something wrong about NoScript, read the FAQ page and/or let me know: I'll try to fix it as soon as I can.

You can also discuss about NoScript on this Forum.

Have your safest browsing experience!