Eric and Donna have been next door neighbors ever since they were children. When Donna first moved in and first met Eric, she punched him in the stomach for looking at her funny. It was at that moment that Eric fell madly in love with Donna. They later became the best of friends and hung out with each other all the time. Eric's love for Donna continued on and on, but he didn't admit his love for her until they were 16 in 1976, when Eric Forman takes his car out of town when explicitly told not to, and impresses Donna who decides to give him their first kiss.
They don't start going out immediately, but take their relationship slowly, unsure how to show their interest in each other and getting advice from their friends on how to act now that their relationship has changed. When the gang goes to a disco, Eric doesn't dance with Donna, but later admits that he hates disco and went because he likes her, which is the first time he tells Donna how he feels about her. They go on to discover many firsts together, like making out at the drive-in and what it means to be exclusive as teenagers, when Eric kisses another girl.
Meanwhile, Hyde is still competing for Donna's affections and they both give her Christmas gifts, while Donna in turn, give both the guys Christmas gifts, although she signals her interest in Eric by giving him the watch he wears for the remainder of the show, while she gives Hyde socks. They go on their first date on Valentine's Day and during the date, Donna unexpectedly becomes intoxicated, which only makes the experience more uncomfortable than it should have been, for Eric especially, as he wanted to give her his class ring. Despite Hyde showing up and professing his feelings for Donna one last time, Donna chooses Eric.
Their relationship becomes very public when Bob accidentally finds out that Midge put Donna on the pill, then Kitty and Ref find out, although Eric and Donna aren't sleeping together. They go to the prom together and consider sleeping together for the first time, but feel that the timing is off. Eric at times gets insecure about how the world views their relationship, as he himself has trouble seeing his own worth and value. This comes to the fore when a guy Eric hates hits on Donna, and when they go to a disco but only Donna is let in at first and Eric is the last to be let in. Eric is also continually insecure about Donna falling for Hyde, noticeably when Donna's parents start fighting and she suffers from it, confiding in Hyde instead of Eric.
Eric and Donna's relationship gradually grows and Donna confesses to Eric that she loves him, only for him to respond that he loves cake. Eric gets his act together after many attempts and tells Donna that he loves her as well. After Donna's parents renew their vows, Donna expresses to Eric that he was the inspiration for her vows and they have sex for the first time. Eric believing he has brought Donna much disappointment by, "Being lame in the sack", is reassured by Donna that sex can only get better from their first time.
Their relationship appears to only have become stronger, yet it gradually starts falling apart, when Donna becomes more serious about her work as a DJ at WFPP, which irritates Eric as Donna is very content focusing on her job. Eric feels that she isn't taking their relationship or him seriously, as she would blow off dates to work. Donna tries to make Eric see how important her job is to her, and that, regardless of all the rock stars she may encounter, she is mad at him for not trusting that she is faithful to him. A lot of their strain in this time stems from Eric's continued insecurity that he's never going to be 'good enough' for Donna or who she really wants to be with later in life. This was already evident when David Milbank hit on Donna and she berated Eric for not trusting her. Eric tries to hold on by giving her a promise ring and Donna returns it to him saying she can't make those kinds of promises, which breaks Eric's heart and he ends their relationship, breaking Donna's heart.
Eric and Donna stay separated, but manage to figure out a way to stay friends. This is shown when Eric goes to pick up Donna to go to the prom, but stays with her while there are tornado warnings in their town. Donna develops a romantic interest in Casey Kelso (Kelso's older brother), which everyone but Eric (and later Michael) seems to approve of. When Casey and Donna break up, Donna runs to Eric to be consoled only for Eric to tell her he wasn't going to be a rebound for her. Distraught, Donna chooses to run away to California with Michael (who on the other hand is running away from Jackie). Eric realizes how much of a mistake he made after talking with his parents and leaves to find Donna, deciding to lay on her bed until she returns, only to find out later she ran away to California with Kelso.
Eric goes to California at the end of summer to tell Donna how much he loves her and that he wants to be with her and they reconcile. Eric decided that he wanted something big for him and Donna and he decided to propose to her on the Water Tower. Their engagement was disapproved by many especially Eric's father Red, who felt Eric wasn't being wise. Eric took Red's cruel punishment and received his blessing for doing so. Eric and Donna decided to move to Madison to start their life together and want to do so but are held back after Red suffers a heart attack.
Donna is still moving away to college, but stays until the last bus to spend Eric's 18th birthday with him. But she proves that she can't leave him because it is too much of an adjustment to her life. Donna and Eric go through premarital counseling because of their pregnancy scare and this is where they decide to stop having sex until they are married. Eric and Donna go through all the premarital events like wedding shopping and even Eric destroying Donna's wedding dress. As the day approaches, Eric begins to have second thoughts after a dream he has. When it was time for the wedding rehearsal, Eric was a no show only to leave Donna in anger. He comes back to explain his cold feet and Donna explains her cold feet as well.
Donna and Eric remain together even after their called off wedding. In the end of Season 7, Eric moves to Africa to teach kids in order to pursue his dream of helping people.
He broke off the relationship with Donna as he could not handle a long distance relationship with her. Donna did move on with Randy Pearson, but she struggled with him as he was not anything at all like Eric or even Eric himself. In the series finale, Eric came back from Africa to celebrate New Years Eve with the family and gang, only to run into Donna and tell her how much he regretted his mistake of breaking up with her. Donna and Eric shared an intimate moment that left the majority of viewers to assume they got back together.
- Their relationship has been one of the show's main focal points.
- Throughout the course of the show, Eric manages to mess up things with Donna only to win her back at the end of many an episode.
- Given that each season does not represent one year, their relationship throughout the show's entirety possibly equals around 4 years.