Was the Holy Spirit poured out on Gentiles as well as Jews?
Yes. Scripture records the gift being given to a whole Gentile household after it was first given strictly to Jews. The six Jewish witnesses with Peter saw it poured out on Cornelius's household, evidenced by their speaking in known languages and magnifying God.
Les explains that as many as came with Peter, these six Jews, saw that on the Gentiles also was poured out the gift of the Holy Spirit. They knew because they heard the Gentiles, the house of Cornelius, speaking with known languages and magnifying God. These Gentiles were talking to fellow men, not to God, and there was no manifestation of an unknown language or a guttural sound. This was the second time the Holy Spirit was manifested by giving the gift of speaking more language than what they were normally living with. The first time it happened to Jews in Acts chapter 2, strictly to the Jew; the second time it happened to a whole house of Gentiles; the third and last time in the whole book of Acts is in chapter 19.
While Peter yet spake these words, the Holy Ghost fell on all them which heard the word.
See the restMore Questions
How did the Jews with Peter know the Gentiles had received the Holy Spirit?
The Jews with Peter knew the Gentiles had received the Holy Spirit because they heard them speaking with known languages and magnifying God.