Yes, a Gentile can give ayin hara, as explained in this article :
The Mishna in Avot spells out the three negative traits that Balaam
"Whoever possesses the following three traits is of the disciples of
our father Abraham; and whoever possesses the opposite three traits is
of the disciples of the wicked Balaam... The disciples of the wicked
Balaam have an evil eye, a haughty spirit and a greedy soul."
On the third occasion when Balaam tried to curse the Jews, it says,
"Balaam raised his eyes and saw Israel dwelling according to its
tribes." Rashi explains that he attempted to cast an evil eye on
them. Thus we learn that Balaam had an evil eye.