Sandra Green is the mother of Rachel Green. She divorced Leonard, the father of her three daughters (the other two being Jill and Amy), as she realized she never loved him any more than Rachel ever loved her jilted fiance Barry, at one point saying while discussing the divorce with Rachel "You didn't marry your Barry honey, but I married mine." In one memorable moment she asked if Monica Geller and Rachel had any marijuana as part of her celebrating her imminent separation from her husband. She also danced with a "wonderfully large woman" at Carol and Susan's lesbian wedding, noting that whilst it was not necessarily something she would pursue, it was "Nice to know I have options". Upon seeing the Ugly Naked Guy, she comments on his actions referring to him as an "unattractive nude man".
Sandra Greene also displays many of the characteristics that Rachel had before she set out on her own, including dependence on others for money, lack of respect for people in minimum-wage jobs, and lenient attitude towards marriage. However, upon seeing Rachel happy in her independent state, she says that she also desires to be independent.
During Rachel's birthday party in Season Two, Sandra and her ex-husband each attended the party, prompting the gang to throw two separate parties to prevent the two interacting. As a last effort to conceal their presence from each other, Joey kissed Sandra while the gang smuggled Rachel's father past them, prompting Sandra to comment that it was the best party she'd been to in years.
When Monica runs Rachel a baby shower in season 8 she forgets to invite Sandra Greene, however invited both of Rachel's sisters, although only Sandra arrived. For a time, Sandra attempted to invite herself to live with Rachel to help her cope with the baby, but Ross helped Rachel see that she needed to learn how to be a mother on her own. Sandra showed a grudge against Monica during the shower for initially forgetting to invite her. Monica sticks up for herself and slams the door on Sandra as she leaves, only to then open the door and chase after Sandra apologizing.
The One With The Lesbian Wedding
Sandra makes her first appearance in this episode when she comes to see her daughter at Central Perk where she worked and later at her apartment announced that she's divorcing Rachel's father. She also stays for Carol and Susan's lesbian wedding and during the reception she says that she danced with a wonderfully large woman and that three other girls made eyes at her before finally saying that it's not something she wants to pursue but it was nice to know she had options.
The One With The Two Parties
Sandra arrives at Rachel's birthday party just a few minutes after her ex-husband arrives there and as Monica opens the door for her and sees it's Sandra she closes it and opens it again when Dr. Green is (for a while) out of sight. Monica claims she thought Sandra was Rachel and she comes in. During the party, Sandra brags everything at Rachel about Leonard and is unaware for the whole night that her ex-husband was also there. At the end of the party, she got kissed on the lips by Joey to prevent her from seeing her ex-husband while Dr. Green walked away and the gang hid Sandra behind them, prompting her to comment that this was the best party she had been to in years.
The One With The Baby Shower
Sandra makes her last appearance in this episode where she was forgotten to be invited to Rachel's baby shower and was called at the last minute. She showed a grudge against Monica throughout the shower and suggested moving into Ross's apartment to help take care of the baby, but Ross manages to change her mind. As she is leaving the party, Monica speaks angrily at her and she walks off. Monica soon chases after her apologizing.
Sandra and her ex-husband, Leonard happened to have an imploding relationship and marriage. It seems that she had only married him for the sake of money and he for her looks. According to Rachel, they barely even spoke (except when they argued). They ended up getting divorced in Season 2 and after that, they were completely unable to be in the same room, as shown when the gang throws Rachel two birthday parties with Rachel's mother in Rachel's apartment and her father in Joey and Chandler's apartment.
Sandra loved her daughter and Rachel loved her back, although Rachel was sometimes exasperated when it came to her mother's snobbishness.
Jill and Amy Green
Sandra's relationship with her other two daughters is completely unknown. It's possible that she must have loved them the same way she had to Rachel, unlike their father due to them not being able to make a great living of their own.
Sandra was very fond of Ross Geller. She considered him a nice person although in "The One With The Two Parties", she thought that Rachel had chosen 'a boyfriend like her (Rachel's) father', but she still had good opinions of him.
It is presumed that Sandra becomes Ross's mother-in-law and Ross becomes Sandra's son-in-law when it's hinted that Ross and Rachel married again.
Sandra also knew Phoebe, Monica, Joey and Chandler. Sandra and Monica were on very good terms throughout the show until the former's last appearance in The One With The Baby Shower due to the latter forgetting to invite Sandra to the party. It is unknown what happened to their relationship afterwards. Sandra also had good relations with Phoebe and also Joey and Chandler, but she likely never gave the boys much thought (Although she did consider the kiss she shared with Joey at the end of Rachel's birthday party as having made it the best party she'd been to in years).
- Sandra appears to be a little kinder (despite her unpleasantness) than her ex-husband.
- Sandra enjoys atkins diets.
- Sandra is the only member of Rachel's family to have not been seen inside Ross' Third Apartment (although she could've if Ross hadn't changed his mind about letting her move in to help take care of Emma) while Rachel and her other family members who appeared on the show were seen inside it:
- Rachel - numerous times between Season 5 and Season 10, especially when being pregnant with Emma;
- Leonard - "The One With The Stripper" when he goes over to yell at Ross for getting Rachel pregnant and not marrying her (although this was a lie) and almost destroying Ross and Mona's relationship;
- Jill - "The One With Rachel's Sister" and "The One Where Chandler Can't Cry" during her brief relationship with Ross;
- Amy - "The One With Rachel's Other Sister" when she comes to borrow a hair-straightener and stay for Thanksgiving dinner and in "The One Where Rachel's Sister Baby-Sits" when she thinks Rachel still lives there;
- "The One With The Sonogram At The End" (First mentioned)
- "The One With The Lesbian Wedding" (First appearance)
- "The One With The Two Parties"
- "The One With The Jellyfish" (Mentioned only)
- "The One With All The Haste" (Mentioned only)
- "The One With The Kips" (Mentioned only)
- "The One With The Rumor" (Mentioned only)
- "The One With The Baby Shower"
- "The One Where Monica Sings" (Mentioned only)
- "The One With The Lottery" (Mentioned only)
- "The One After Joey And Rachel Kiss" (Mentioned only)
- "The Last One, Part 1" (Mentioned only)