This study attempts to analyze the slang and idioms found in Gravity Falls Season 2. It includes the findings of slang and idioms found in Gravity Falls Season 2, the meaning of slang and idioms found in Gravity Falls Season 2, and the contribution of slang and idioms found in Gravity Falls Season 2 to Lexical Studies. This study used a qualitative descriptive study. The data were collected through documentation. The method of analysis which was used in this study was content analysis. The researcher in conducting this analysis referred to both previous studies that discussed slang and idiomatic expression from Zarbaliyeva (2012) and Ardita (2017). This study shows 118 slang and 100 idioms in ten episodes of Gravity Falls Season 2. The most frequently Slang types in the dialogue were Freshness and Novelty with 51 times, and the most frequently Idioms types were Compositional Transparent with 35 times. Findings demonstrated that the contribution by learning using some slang and idioms in Lexical Studies enabled the learners to increase their knowledge about them and improve their communicative skills. Hopefully, it could enrich students’ knowledge about slang and idioms and increase student vocabulary. Both slang and idioms were needed if the students wanted to speak English fluently.