As of right now that is not customizable. This may be possible in future versions.

I would love to see a solution to this as well.

What good is clearing my history if I can't take even a single damned thing out of the "top sites"??!!! Major, unbelievable, oversight. Absolutely ridiculous.

I hope they can add an option 'to remove/disable' or 'to clear' the long list of sites in Top Sites. I find it to be useless.

I've been a Firefox user for years and one reason I chose Firefox was that I could control my privacy. After installing the Android app and syncing my account I discover that despite setting maximum privacy options in the browser including no-history I have actually been tracked the whole time, but not only that but will constantly have my "top sites" shoved in my face every time I use it, AND that I have no ability to modify or delete these either.

I'm going to live in Google-incognito. You've lost a previously loyal user with this heavy handed nonsense.

Inept

unintalled fiefox. waiting for future version that have better privacy. My tablet is shared and I do not want people what top sites I visit.

There is a way to delete individual entries in "Top Sites".

Tap and hold on the site name in the list. A popup should appear showing, OPEN IN NEW TAB, SHARE, REMOVE, ADD TO HOME SCREEN

The REMOVE option will delete the site from the list.

You can delete all top sites (and everything else) from Android settings. Go to Settings>Apps>Firefox>Clear data

This for sure also deletes bookmarks, cookies, passwords and so on.

{ed.} This comment refers to the desktop version of Firefox. It has nothing to do with Firefox for Android {/ed.}

kbrosnan is, well, WRONG:

http://support.mozilla.org/en-US/kb/new-tab-page-show-hide-and-customize-top-sites#w_how-do-i-turn-the-new-tab-page-off

If you are concerned about your privacy, you can turn this feature off completely:

   In the Location bar, type about:config and press Enter.
       The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise!, to continue to the about:config page. 
   Type browser.newtab.url in the search box.
   Double-click the browser.newtab.url preference and change the url from about:newtab to about:blank. Alternately, you can change it to about:home for the Firefox Google home page, or type in your preferred home page, for example google.com.
   Click OK and close the about:config tab. 

Using the above method, you can turn off the top sites feature completely AND customize the new tab page with a blank page, OR your home page, OR whatever page you want.

Mods: why are you saying we can't turn off or customize the Top Sites page when you actually CAN?

No nested replies? Okies....

Sadly, occulus' response doesn't apply to the mobile version of Firefox (to which the OP is referring).

a) Why inconsistency in something so basic between platforms? b) Given this, why aren't the support forums for platforms better separated?

Locking this post as it has gone off topic.