Sydney Phillips owns one terrific smile — and crossover move.

“My favorite, though,’’ the seventh-grade guard said this week, “is my behind-the-back move. I just love playing basketball.

“I’ve been playing since I was 2 years old. I like the rush of the game, the challenges of the game. There’s always something new.’’

She loves playing basketball for St. Theresa School in Kenilworth, NJ. As a sixth-grader last year, she played varsity girls basketball and was voted an All-Star by her teammates. She was looking forward to playing again this year, and wants to go on to play in high school and college.

However, instead of being on the court, Sydney’s situation is now headed to court.

In late October, the girls’ basketball season was canceled because the school didn’t have enough players to field a team, the school says.

Sydney still wants to play for St. Theresa and her family thought her only school option at that point was to play with the seventh-grade boys’ team.

Not happening. Boys play with boys and girls play with girls, the family was told by the director of the Office of Youth Ministry and school officials.

As a result, Sydney’s father, Scott, decided to take legal action against the Archdiocese of Newark and St. Theresa to allow her to play on the boys’ team this season.

“This is not for money, we just want Sydney to be able to play basketball,’’ Scott Phillips told The Post.

An order to show cause for a preliminary injunction to allow Sydney to play is scheduled for Jan. 5 in Superior Court of New Jersey, Chancery Division: Essex County.

Scott Phillips said the National Organization for Women will have representatives at the hearing.

All of this began on Halloween, when Sydney’s parents were informed by another parent there would be no girls’ basketball team this year.

“They said there was not enough interest and that application forms were not returned on time,’’ Scott Phillips said. “Even though there was no return date on the forms and there were likely enough players to field a team.’’

Phillips went to school officials the next day to try to get the matter cleared up.

He said last year there were similar issues with player registration, but the situation got resolved and there was a team. Phillips’ wife, Theresa, coached the team for a fifth season and she was hopeful of coaching at the school again this year.

This year, the father said, the school would not accept Sydney’s application for the boys’ team, well before the season started, and, Scott Phillips said, “mailed it back to me via registered mail.’’ He then again dropped off the application at school.

A Nov. 8 letter from the school to the parents, noting the application was being returned, was signed by principal Deacon Joe Caporaso and athletic director Mr. Anh Bui. It stated the application was being returned because the “Archdiocese of Newark, Office of Youth Ministry Athletic League, runs separate divisions for both boys and girls in Grades 5-8.

“Since then the Archdiocese does not permit boys to play on girls’ teams and girls to play on boys’ teams.’’

Evidently, even when there is no girls’ basketball team at St. Theresa School.

The letter went on to say, “It is our understanding that you and your husband were informed of this policy by the Director and Associate Director of the office of Youth Ministry as well as by Mr. Bui, who is the Director of Youth Ministry at St. Theresa’s.’’

The opposition brief filed to the court Tuesday by the archdiocese’s attorney Christopher Westrick states “the plaintiff failed to timely turn in her required forms to play basketball … the plaintiff argues there is no rule that forbids her to play with boys, when the rules clearly provide for separate boys’ and girls’ divisions.’’

“I want to see the written rule that says a girl can’t play on a boys’ team and no one will provide me with the written rule, so that’s why we had to take it to the next step,’’ Scott Phillips said.

Reached at the school, Caporaso declined comment. Westrick also declined comment.

Now Sydney, a member of the National Junior Honor Society, an altar server and student council treasurer, just wants the situation resolved. She welcomes the challenge of playing with the boys.

When you are 12 years old — “13 in a few days,’’ Sydney said with a smile — and your basketball heroes include old-school legends Michael Jordan and Larry Bird, you are not going to be afraid of jumping another hurdle.

She believes she would be one of the best players on the boys’ team, if not the best. Because there is a no-cut policy, she would not be taking away a roster spot from another player.

“I love basketball, and I just want to play for my school,’’ Sydney said after showing off that behind-the-back move at nearby David Brearley High School gym. She has been going to St. Theresa School since Pre-K.

“When I found out I couldn’t play, I was really bummed. I went to school that next day and told one of my teammates who is in eighth grade and she was really sad because she couldn’t play.’’

I grew up in Kenilworth. St. Theresa’s Church was my church. So I understand when Sydney said she did not want to be shipped out to another school to play for a girls team. St. Theresa School is her school.

For her Christmas gift, Sydney wants to be able to join her school’s seventh-grade boys’ basketball team, one of three boys’ basketball teams the school offers.

If there were a girls’ team, she would happily play for that team.

“This isn’t about religion,’’ Scott Phillips said, “it’s about a girl who wants to play basketball. The school offers co-ed basketball paid clinics. It’s OK for Sydney or any girl to play there with the boys.’’

“At basketball camp at Roselle Catholic, I play with the boys all the time,’’ Sydney said. “It’s fun.’’

Meanwhile, Sydney is keeping busy, playing rec basketball and for the St. Theresa School volleyball team.

“It’s fun, but it’s not basketball,’’ she said.

Asked how well she does in girls’ volleyball, Sydney said, “It’s not girls’ volleyball, it’s co-ed.’’