Leah Patterson (also Poulos and Patterson-Baker) is a fictional character from the Australian soap opera Home and Away, played by Ada Nicodemou. She made her screen debut during the episode broadcast on 22 March 2000. Leah is one of the longest featured characters in the serial's history and has been involved in storylines including the deaths of her husbands, her many relationships, surrogacy, suffering anxiety and the victim of racism. Nicodemou took a temporary break from Home and Away in late 2012, following the birth of her first child. She returned from her break on 19 June 2013.

In 1999, Nicodemou was approached by the producers of Home and Away with an offer of a six-month contract. Nicodemou was not required to audition and began filming in November that year. Before Leah appeared on-screen, Nicodemou had already been offered an extension to her contract. She had already spent four years in the cast of television programme Heartbreak High. Nicodemou took this into account when she accepted the role, only intending to remain with Home and Away for the duration of her six-month contract. However, she later decided to stay in the role because she "almost immediately fell in love with the show and the people". Ten years later, Nicodemou said was happy to carry on portraying Leah for the foreseeable future. She explained the reason behind her longevity was because Leah was "still evolving", which kept the role enjoyable.

Nicodemou is one of the longest serving cast members of Home and Away.

Leah first appeared in Home and Away during the episode airing on 22 March 2000. Upon her introduction, she was described as "a girl with a big heart, a big secret and a big future that was all hers." In Nicodemou's first interview about the role, she remained secretive about plans for the character, but said Leah has "a big secret" and arrives in Summer Bay alone. Leah was given links within the serial almost immediately. Leah takes a job as a chef at the local diner and moves into a house with Vinnie Patterson (Ryan Kwanten) and Tom Nash (Graeme Squires). However, Leah "quickly realises" that her secrets will not remain her own for long because Summer Bay is a "little town". Producers decided to give Leah a "huge and juicy love story" with Vinnie, this was to help Leah settle into the serial more quickly.

I really love Leah. I've always said she's the type of person I'd love to have as a friend - because she allows me to play so many different areas, from comedy to drama - and also because she's one of the few single-parent characters in Australian drama. She's someone a lot of people can relate to because she's just getting on with life and dealing with problems like running a business and bringing up a son. I think she's better doing that than if everything went her way.

— Ada Nicodemou on Leah.

Yahoo!7 describe Leah as "a single mother who has a strong work ethic and stands up for what she believes in." "Leah has a confidence about her that makes her shine. She's easy going and fun loving." Also adding: "She's passionate about life and will cry at the smallest injustice and boy, can she talk! But she is also a good listener and she will always provide a shoulder to lean on." Soap opera reporting website Holy Soap describe Leah as being: "Fun, confident and passionate, Leah is a big talker and a great listener." They have also observed her as being "especially unlucky in love". The Channel Seven make-up department cut and colour Nicodemou's hair for Leah's on-screen appearance. She has also admitted that she has not control over the amount of make-up the stylists apply to get her into costume.

In 2009, Leah struggles with the pressures of life. Nicodemou said she enjoyed portraying Leah's struggle as fights to cope with "work, her son and herself". She said it makes Leah "a real character and makes her challenging to play". In 2011, Nicodemou said that she would like Leah to act out of character and become evil for a couple of episodes and have a nervous breakdown.