Season One
- "Our babies will be smart and beautiful." - Leonard, 1.01
- "You know, you two make a cute couple." - Mary Cooper, 1.04
- "Leonard, you are so great. Why can't all guys be like you?" - Penny, 1.06
- "Penny, we make such a great team." - Leonard, 1.07
- "Don't worry baby, I got you." - Leonard, 1.14
- "I am so sorry you didn't get your party. Happy birthday anyways." - Penny, 1.16
- "Just once, I wish I could go out with someone who's nice, and honest, and who actually cares about me." "What about me?" - Penny and Leonard, 1.17
- "Yes, I will go out with you." - Penny, 1.17
- "The cat's alive." - Penny, 1.17
Season Two
- "Penny with another guy, tres awkward." - Howard Wolowitz, 2.02
- "Merry Christmas." - Penny and Leonard, 2.12
- "Oh Leonard, honey. If we started living together, I wouldn't be able to keep my hands off you." - Penny, 2.14
- "Now this time, you're gonna lick the salt off my neck, do the shot-whoops!-and then bite the lime." - Penny, 2.15
- "We? No no no no, you had your chance to be 'we' for like a year and a half now. Right now you are you, and you are screwed!" - Leonard, 2.16
- "There. Butt print." "No, it's too small and too...perfect." "Thank you!" "You're welcome!" - Penny and Leonard, 2.16
- "Penny...I got this." - Leonard, 2.16
- "Hey, Leonard, what's going on with Dr. Wackadoodle?" - Penny, 2.17
- "Everything was good, and really hot. Then I said 'oh, Penny' and right where she was supposed to say 'oh, Stuart,' she said...your name." - Stuart, 2.22.
- "Leonard, could you pass the soy sauce, please?" "I'm sorry, are you talking to me?" "Yeah, I said 'Leonard'." "Yes you did, didn't you?" - Penny and Leonard, 2.22
- "I'm gonna miss you." - Penny, 2.23
- "It means I wish you weren't going." - Penny (to herself) 2.23
Season Three
- "Leonard, you're back!" - Penny, 3.01
- "I missed you so much. I couldn't think of anyone else when you were gone." - Penny, 3.01
- "It's a snowflake. From the N orth Pole. It'll last forever." - Leonard, 3.01
- "Aw, you're my little homunculus!" - Penny, 3.03
- "Wanna get a little crazy? Let's slide over to Sheldon's spot and make out." - Penny, 3.04
- "Wow. You are a genius." "Not really. I Googled how to do that." - Penny and Leonard, 3.05
- "So yeah, anyway, that's my boyfriend. He is really smart." - Penny, 3.06
- "I wish Penny were here." - Leonard, 3.08
- "I did not settle for Leonard." - Penny, 3.09
- "I just want to know enough so I can talk to Leonard about his job." - Penny (about physics) 3.10
- "Now, how could you not tell me you were in a relationship with this lovely, charming young woman?" - Beverly Hofstadter, 3.11
- "I want you to take very good care of this young woman." - Beverly Hofstadter, 3.11
- "I can’t believe it. If I hadn’t been working the dinner shift, I would’ve run right into the robbers." "Hey, there’s no reason for you to be scared." "I’m not scared. I would’ve gone all Nebraska on their asses." - Penny and Leonard, 3.13
- "Leonard...you're giggling in your sleep." - Penny, 3.14
- "We’re going to Switzerland to see the CERN supercollider! And ski. We’ll also go skiing." "We’re going skiing in Switzerland?!" "Well, you’ll ski, I’ll fall, but, yeah, we will be in Switzerland for Valentine’s Day." "Oh, my God, Leonard! That’s incredible!" - Leonard and Penny, 3.15
- "Sheldon tried to take the ring and I punched him." "That's my girl." - Penny and Leonard, 3.17
- "You are my boyfriend. Nothing you do is silly to me." - Penny, 3.17
- "Oh, my God. I'm lying in bed with a beautiful woman who can quote Yoda. I love you, Penny." - Leonard, 3.19
- "You have to know how much I care about you." - Penny, 3.19
- "Yes, you will (meet a girl someday), and she’ll be beautiful, and kind and sexy and funny and everything you ever wanted in a woman...and you’ll fall hopelessly in love and give her your heart. And she’ll take it and grind it into pathetic, little pieces." - Leonard, (to Raj) 3.20
- "I think we can do it...be friends. You and me." - Penny, 3.20
- "You have destroyed my ability to tolerate idiots!" - Penny, 3.23
Season Four
- "Why did you terminate your relationship with (Leonard)?" "I don't know." - Amy and Penny, 4.08
- "How will you react if in the future you become ready for it, and Leonard is unavailable because another woman has realized he is…to use your words, a great guy?” “…you know, I really don’t want to play anymore.” – Amy and Penny, 4.08
- "You're the only boyfriend my parents ever approved of." - Penny, 4.09
- "Please, please, please don't give up on her!" - Wyatt, to Leonard about Penny, 4.09
- "If Zack and I had gone to a regular club or a party it would have been fine, but with this, all the costumes, and you..." "What about me?" Long Pause "Nothing. Let's go to the party. How do I look?" "I guarantee you'll be the prettiest girl there." – Penny and Leonard, 4.11
- "The good news is we have a Wonder Woman." "What's the bad news?" "Superman's probably not getting laid tonight." Howard and Raj, after Howard overhears a conversation between Leonard and Penny. (Superman: Zack.)
- "Maybe it wouldn't be the worst idea in the world to...violate the Neutral Zone for one night." - Penny, 4.13
- "If anything I'm quite pleased Leonard has found someone that makes him so happy..." - Penny, while breaking down in tears, 4.16
- "That's really romantic." "Yeah, it was." - about Leonard, 4.17
- "Seriously, what would you do without me?" - Penny, 4.18
- "I screwed up. Leonard's a great guy. I should never have broken up with him." - Penny, 4.24
Season Five
"I hurt Leonard. I hurt Raj." - Penny to Amy, 5.01
"I'm so proud of you." - Leonard, 5.01
"I'm so proud of you." - Leonard, 5.01
Cast Quotes
- "I want Leonard and Penny to get married." - Jim Parsons, 2009
- "Penny's molding Leonard into the man that she wants to marry." - Kaley Cuoco, 2009
- "I think they're great." - Johnny Galecki 2009
- "Penny and Leonard will, I mean, they're that...it's tho...it's them!" - Kaley Cuoco Comic-Con 2010
- "I do deep down know in my heart, and hope in my heart, that at the end of the day, they will end up together." - Kaley Cuoco, Comic -Con 2010
- "Those are the scenes that we really take close care in rehearsing. We rehearse those scenes between Leonard and Penny more than any other, because they're really specific in what you want to suggest." - Johnny Galecki, Comic-Con 2010
- "Penny has to end up with Leonard!" - Johnny Galecki, Golden Globes 2011
- "I always think they're perfect for each other...." - Big Bang Theory Writer, Golden Globes 2011
- "She doesn't realize she's in love with him..." - Kaley Cuoco, Golden Globes 2011
- "I do feel they are the loves of one other's lives." - Johnny Galecki, 2011