Gwen - There's one thing I always wanted to ask Jack. Back in the old days. I wanted to know about that Doctor of his. The man who appears out of nowhere and saves the world; except sometimes he doesn't. All those times in history where there was no sign of him.. I wanted to know why not. But I don't need to ask anymore. I know the answer now: Sometimes the Doctor must look at this planet and turn away in shame. I'm recording this in case anyone ever finds it, so you can see. You can see how the world ended.
Series 4: Miracle Day

Gwen: ...Special Ops! I'm Special Ops...I'm with Torchwood.
Soldier: Don't mess with me, little girl. You're not with Torchwood. And even if you were-
Jack: -You'd have put out the welcome banners. Now, first of all, she's no little girl. From where I'm standing, all the right curves in all the right places...but she is Torchwood, we both are, and we'd appreciate it if you'd leave us to do the real work. [holds hand out to Gwen] Shall we?

Gwen: [talking about getting married] It'll happen for you one day, Tosh. There's always Owen.
Tosh: I don't think so. "In sickness and in health, 'til death do us part". It's gonna sound like a bad joke.

Gwen: All the things I fought with Torchwood. And what stops me? Red tape.

Gwen: Anyway, so how's my little girl?
Rhys: Don't call me that, Gwen.
Gwen: Very funny.

Gwen: But Rex, we've got to do this. And I'm gonna to tell you why. Because I'm standing here and I'm staring at Oswald Danes. And he chose when that girl lived and he chose when that girl died. And no one should have that power. Not the rich, not the mad, not anyone.
Oswald: You're choosing now.
Gwen: Yeah, you watch me.
Oswald: You'll kill Jack and Rex and that girl Esther--all of your Torchwood team. You'll kill them all.
Gwen: Yeah. Yeah.
Oswald: You are magnificent!

Gwen: I've got to get Rhys back!
Jack: Yea, you're so in love with Rhys, you spend half your time in Owen's bed. [Gwen punches Jack]

Gwen: Just get my dad out, Rhys, and I'll phone you tonight.
Rhys: It's already tonight!

Gwen: Oh, um, I'm sorry, I'm sorry, I get a bit confused, which one's UNIT?
Jack: Intelligence. Millitary. Cute red caps. Acceptable face of intelligence gathering on aliens. We're more ad hoc, but better looking. [emphasis on "better looking" directed at Martha]

Gwen: She's going out with a frozen soldier from 1918.
Jack: Nobody's perfect.

Gwen: So much for tying him up.
Rhys: I've never tied up a person!
Gwen: "Men are good at knots." How many times have you told me that?
Rhys: At Christmas!
[having been attacked by a sniper in a helicopter]

Gwen: So, what sort of vision did you have? We all saw people we loved, asking us to open the Rift. Who did you see?
Jack: Nothing. I didn't see anyone.
Gwen: Jack? What visions would have tempted you?
Jack: [sighs] The right kind of Doctor.
[Jack gets up and walks out of the room. He walks through the Hub, then stops. He walks across the room, staring at something. He bends over with a wide grin on his face in front of the hand in the jar. The hand is bubbling and glowing. The sound of a TARDIS materialising fills the room and blows paper around. Jack grins and runs offscreen (later continuing to Utopia). Gwen walks in as we hear the TARDIS start to dematerialise.]
Gwen: Jack!
[The TARDIS noise fades away as the others walk in and notice the mess]
Owen: I thought we tidied up in here.
Gwen: Did any of you see Jack on your way in?
Ianto: No. Why?
Gwen: [Arms folded, she turns to face the direction the noise came from] Something's taken him. Jack's gone.
Series 2

Gwen: That was your last chance.
Lyn: Yeah? And what're you gonna do about it? If you're the best England's got to offer, then God help you.
Gwen: I'm Welsh. [punches her]

Gwen: They move the category ones at 6am. They take them to the module--
Dr. Patel: Sorry. Not my department.
Gwen: Really? Is that so? Well do you even know what your department is, Dr. Patel? Do you even know what really happens here? Do you know what happens in the module?
Dr. Patel: Like I said, I'm rather busy.
Gwen: They burn people. They burn living people.

Gwen: They've got my dad, Jack. They've got my dad.