Yoda (and other Jedi masters) trained the students. Obi Wan was supposedly trained by Yoda when he was a student. The moment when he became an apprentice he was tied to Qui-Gon as his master to instruct him.

Nice one, thank you.

Pretty much what @Astro The Blue Boi said. Yoda was responsible for training many of the jedi initiates. Back when they're still younglings, Yoda is one of the main jedi masters that oversees their training.

Great! Thanks.

Yes

What the others said. You can see Yoda teaches the younglings in Episode II and in Clone Wars, it is said that all Jedi were trained by Yoda and they share a strong bond with him. George Lucas explained, Yoda trains the kids until they are like 8 years old, teaching them basic Jedi philosophy, then they get their Jedi Master. So Obi-Wan was taught by Yoda, then his training was finished by Qui-Gon, making Yoda to be some kind of grandfather for all the Jedi (given the fact that they often refer to their masters as being like a parent to them.) Except for Anakin, of course, as Lucas said, his problems are basically stemming from not being taught by Yoda from the beginning, and the basics were missed out. This is why Obi-Wan laments, he thought he can be as good teacher as Yoda, but he couldn't teach Anakin how to resist the dark side, after all.

@WriterBuddha wow, I didn't know that about Anakin missing out. That makes a massive amount of sense with what Obi-Wan say in TROJ.

He probably said this because George Lucas didn't plan that ahead lol

To quote someone's post from TV Tropes: "when Obi-Wan referred to Yoda as the one who trained him, he was talking to Luke who was barely conscious and freezing out in the snow. He probably skipped over the details and got straight to the point."

Ha ha yeah good point!