Tenchi Muyou!

Made by the same company and has the same plots and story lines (romance). Instead of having 6 guys chasing 1 chick, there are 6 chicks chasing 1 guy. It involves magic and time travel as well as showing how fragile the human mind is. 

A normal schoolboy is soon wrapped up in a bizzare reality where he is actually something special. Both have a strong storyline and developing characters whilst not being too serious; incorporating a lot of comedy. 

Women from another world/planet being protected by a single (and sometimes foolish) man. Lots of ecchi, of course. 

A more upbeat version of a harem style anime, only this time it involves battling demons with magic 

Tenchi Muyou! started the out of this world harem anime, the monogatari series starting with Bakemonogatari follows in Techi's footsteps. The writing of Nisioisin is held strong in the anime adaptation. The wordplay is difficult to translate but the great conversations and interactions make this a top notch anime.  

Space, Space Battles, Mysterious Characters, and the same general type of feel. Each are unique on its own, but similar in set up. 

Tenchi Universe is similar to The Melancholy of Haruhi Suzumiya because it has the same: high school kids with powers thing. I think that Tenchi in Tokyo might be similar to The Melancholy of Haruhi Suzumiya but i havn't seen it. 

Both are Harem shows with characters very much like eachother, comedy is the basic premis but they also have their touching moments too. 

both the main characters are simiple guys surounded by hot alien chicks, one more so than the other. they both have alien royal families the pressuring the guys to get married. they are similar in other aspects other than the plot; they are both funny, ecchi, and also have some action seens - tenchi more so than valkyrie. 

Both of these comedic shows have an ensemble of characters that revolve around a seemingly normal human protagonist but has a bloodline lineage of otherworldly beings. The main protagonists live day to day lives on earth and surrounded by these otherworldly characters. Hilarity ensues when they face day to day mundane problems and scenarios. It feels like watching a sitcom. There are heart-warming yet fun moments in the series. Much like a festival that you don't want to end. I want to avoid using the word harem, but it doesn't change the fact that the protagonists are surrounded by characters of the opposite genders but develop more of a platonic relationship in a love hate kind of environment. If you enjoy comedy series' that revolve around a loveable ensemble and fun times, you'll love these shows. read more 

both are very funny comedies as well as having one male lead that has a lot of girls that love him as well as both having action in them as well besides just the romance and comedy. so i think a must watch if your a fan of one or the other. 

This animes are VERY similar. Both had space pirates, galactic government, in love princess, super powers, funny situations.... And the character of the both anime was design by Masaki Kajishima.  

Another harem anime, El Hazard is very similar to the Tenchi Muyo series, hence the story is based in a fantastic, medieval-style world. If you like a mix of comedy, romance and action, try it now!