Ben Tennyson (Classic)/Love Interests

===Kai Green===
See Article: Relationship with Kai Green
===Julie Yamamoto===
See Article: Relationship with Julie Yamamoto
===Elena Valadis===
Elena Valadis is one of the Plumbers' kids and a former member of Ben's soccer team. Ben met Elena when he was 13 and had to convince his soccer teammates to let her join. She appeared in the live-action film Ben 10: Alien Swarm.
Elena also appeared in Revenge of the Swarm, where she served as the Queen of the Hive. Victor Valadis attacked Ben at night, so the trio went to her to find whether she knew anything about the Microchips. Later, when Ben mentioned Julie, it made her angry and jealous, and she kidnapped her in order to keep Ben all to herself. They almost kissed, but her plan was revealed to Ben, and he saved Julie. Elena, being possessed by the Hive Queen, encountered Armodrillo and choked him with the Microchips. However, she was convinced by Julie to not to do so. She willingly sacrificed herself in order save Ben, proving how much she liked him and that there was still the Elena that cared for him. Ben became sorry for her, understanding how much she had liked him. At the end of the episode, the Microchips reformed, revealing she was still alive.
Elena appeared in The Perfect Girlfriend disguised as Julie. As Julie, she tried to do everything to make Ben happy. Once Ben found out Julie was Elena, he tried to reason with her, but when the real Julie turned up, he ended up fighting her as Ultimate Echo Echo, during which she choked him with the Microchips again. Julie told Elena that if she killed him, then no one could have him. At the end of the episode, Elena retreated into the sewer, "knowing what hate feels like" indicating that she now had a hatred for Ben and promised to return.
===Eunice===
The Unitrix's pod was discovered in the forest at the same time Ben's team was driving for a camping trip. After encountering her, she stayed with them for the day, bonding with Ben (who had recently broken up with Julie). The two of them were soon attacked by Sunder, who shut Eunice down and attempted to get away before Gwen and Kevin stopped him as Kevin restarted the Unitrix again. While the four of them scuffled with Sunder that led to a muddy area, Azmuth arrived, broke up the fight, and cleared things up. Following a brief argument, Ben allowed Azmuth, under a compromise, to take on Eunice as one of his assistants on Primus.
In Simian Says, Eunice kissed Ben on the cheek.
===Emily===
Emily briefly dated Ben, but the reason they broke up was that Ben went "hero" and left Emily on a 200-foot-tall watchtower, causing Emily to get angry at Ben.
===Ester===
When Ester first met Ben in Hot Stretch, they fought for the fusion device. When she realized the other Kraaho were doing evil things, she joined Ben's team. She introduced him to her friends, and they played an alien version of hockey. Ben turned into Water Hazard and splashed everyone with water to cool them down, even when Ester told him not to. He then brought her a towel, and she blushed as he gazed at her. She turned the water floating around him into snowflakes and ran off laughing. Rook told Ben she liked him. When she became the chief, she hugged Ben and told him she and her kind would be good neighbors. Later Ester's friends called Ben her boyfriend, and Ben at first denied it, but then excitedly asked Rook if he had a chance with her.
In Rules of Engagement, Ben offered to help clean up the Hot Spot with her. She excitedly agreed, wrapping her arms around his arm. She also stated that she is fond of Mr. Smoothy.
Sometime before Return to Forever, they went on a movie date.
In Catfight, Ester was in a double date with Ben, Rook, and Rayona. Later in the episode, she hugged Ben, and the two ran off to watch Sumo Slammers 6 3D again.
In Fight at the Museum, Ester invited Ben to the Bellwood Museum for a date, but Ben, not knowing it was a date, brought Rook since Rook enjoys museums. Ester was shown to be horrified when she heard that Ben and Kai end up together in the future Spanner comes from, while Ben himself stated there was no way that was going to happen.
Later in The Most Dangerous Game Show, feeling that Ben really was destined to be with Kai, Ester decided to let go of him. While trying to talk to Ben, who she couldn't get in contact with, Ester ultimately fell in love with Antonio. Eventually, Ester made her feelings known to Ben, breaking up on good terms, even stating she still liked him while remaining friends.
===Attea===
In The Frogs of War: Part 2, Bullfrag infiltrated Attea's team and from the moment she saw him, Attea had a crush on him. When they met in the cell block of Plumber Headquarters, Bullfrag came up to her and started flirting, taking note that his new form showed her in a whole new light. Attea was a bit flustered, but started flirting back, only to be knocked out by a mana blast by Gwen. Bullfrag blamed his crush on Attea on his Incursean DNA.
At the end of the episode, when leaving Earth, she gave Ben the offer to come with her and "Ditch that monkey face and turn into Bullfrag again". He promptly declined. Attea gave him a kiss to the back of his head with her long tongue, winked, and took off.
She later decided that Ben was her only option for a mate in Catfight. However, Ben later convinced her that she was capable of ruling on her own.
===Drew Saturday===
In T.G.I.S., Ben gained a crush on Drew Saturday the minute he saw her. She responded to Ben saying, "right back at ya". When Doc told Ben, Rook, Zak, and Fisk that Dr. Animo and his Chupacabra army were attacking Mr. Baumann's store, Drew offered to stay behind to look after the petrified Gilford Bromley. Ben, though, suggested that Rook stay behind, and Drew come with him, telling them that they might need her medical expertise. Later, when Ben, Rook, Zak, and Fisk arrived at the airship to stop V.V. Argost and his army of cryptids, Doc and Drew revealed themselves and told them that they escaped moments before Argost showed up. Ben then instantly told Drew that he was happy that she was okay, causing Zak to remind him that Doc was okay too. At the end of the episode, Ben told Zak how it was a pleasure to work with him and his mom. He then took a photo with Zak, Doc, Drew, and Fisk as Four Arms.