There is almost an innumerable variety of spellings of the name. Below is list of nearly 60 different variations of the name for which records exist (according to the Consolidated Jewish Surname Index at Avotaynu).

GABRELIOVICH, GABRELOVICH, GABRIALEVICH
GABRIALOVICH, GABRIELEVICH, GABRIELEWICZ
GABRIELEWITZ, GABRIELIEVICH, GABRIELIOVICH
GABRIELOVICH, GABRIELOVITZ, GABRIELOWICZ
GABRIELOWITZ, GABRIELYOVICH, GABRILEVICH
GABRILIAWITZ, GABRILIOVICH, GABRILOVICH
GABRILOVICZ, GABRILOVITCH, GABRILOVITZ
GABRILOWICZ, GABRILOWITCH, GABRILOWITSCH
GABRILOWITZ, GABRIOLOVICH, GABRIOLOWITCH
GABROLEVICH, GABRYELEWICZ, GABRYELIOWICZ
GABRYELOWICZ, GABRYJELEWICZ, GABRYJELOWICZ
GABRYLEWICZ, GABRYLOWICZ, GAVRIELOVICH
GAVRIELOWITZ, GAVRILEVICH, GAVRILEVITCH
GAVRILOVIC, GAVRILOVICH, GAVRILOVITZ
GAVRILOWITCH, GAVRILOWITZ, GAWRALOWICZ
GAWRILIOWICZ, GAWRILOWICZ, GAWRILOWITZ
GAWRYELOWICZ, GAWRYLEWICZ, GAWRYLOWICZ
GEBRIELOWITZ, GEBRILOWICZ, GHABRILOVITSH
GHABRIYELOVITSH, GOBRIOLOVICH, GOVRILOVICH

Additionally, various members of the family also altered the name to better fit new cultures which they entered.

Variations of the name include:

D'Gabriel (Latin)
Gabriel (American)
Gabrielove (French)

ARE ALL GABRILOWITZS RELATED?

Well-the obviously answer is most likely not ALL Gabrilowitzs are related.

I have researched my Gabrilowitz family as well as ALL INSTANCES of the name appearing in domestic and international telephone directories, online directories, genealogical directories, various books on Jewish/ Russian history, etc., and amazingly, I have found probably less than 350 occurrences of the name (in all its variations) across all of those resources. And that includes about two centuries of information!

A recently performed genetic test did NOT show a match between the descendants of Pheitl Gabrilowitz and the family of Ossip Gabrilwitsch. Therefore we have genetic evidence that at least two Jewish Gabrilovich families adopted the surname in the Western provinces of the Russian Empire.

The earliest ancestor in my branch of the family, Pheitl Gabrilowitz has hundreds of descendants. Thus making the case, that just one or two early 19th century ancestors can make for a lot of Gabrilovichs.

Now, I do see that there are folks with the name who appear not to be Jewish. These "Gabrilowitzs" typically use the Polish-style variation Gabrylewicz or Gabrilowicz. There are also many Serbians with a variation of the name, typically with a V as the second consonant, such as Gavrilovich, who certainly appear to be non-Jews.

My speculation is that there are between 2-4 distinct Jewish Gabrilovich families accounting for the large majority of people who carry the name.